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They are listed here in alphabetical order. <table class="docutils align-default"> <thead> <tr class="row-odd"><th class="head" colspan="4">Built-in Functions</th> </tr> </thead> <tbody> <tr class="row-even"><td><div class="line-block"> <div class="line">A</div> <div class="line"><a class="reference internal" href="#abs" title="abs"><code class="xref py py-func docutils literal notranslate">abs()</code></a></div> <div class="line"><a class="reference internal" href="#aiter" title="aiter"><code class="xref py py-func docutils literal notranslate">aiter()</code></a></div> <div class="line"><a class="reference internal" href="#all" title="all"><code class="xref py py-func docutils literal notranslate">all()</code></a></div> <div class="line"><a class="reference internal" href="#anext" title="anext"><code class="xref py py-func docutils literal notranslate">anext()</code></a></div> <div class="line"><a class="reference internal" href="#any" title="any"><code class="xref py py-func docutils literal notranslate">any()</code></a></div> <div class="line"><a class="reference internal" href="#ascii" title="ascii"><code class="xref py py-func docutils literal notranslate">ascii()</code></a></div> <div class="line"> </div> <div class="line">B</div> <div class="line"><a class="reference internal" href="#bin" title="bin"><code class="xref py py-func docutils literal notranslate">bin()</code></a></div> <div class="line"><a class="reference internal" href="#bool" title="bool"><code class="xref py py-func docutils literal notranslate">bool()</code></a></div> <div class="line"><a class="reference internal" href="#breakpoint" title="breakpoint"><code class="xref py py-func docutils literal notranslate">breakpoint()</code></a></div> <div class="line"><a class="reference internal" href="#func-bytearray"><code class="docutils literal notranslate">bytearray()</code></a></div> <div class="line"><a class="reference internal" href="#func-bytes"><code class="docutils literal notranslate">bytes()</code></a></div> <div class="line"> </div> <div class="line">C</div> <div class="line"><a class="reference internal" href="#callable" title="callable"><code class="xref py py-func docutils literal notranslate">callable()</code></a></div> <div class="line"><a class="reference internal" href="#chr" title="chr"><code class="xref py py-func docutils literal notranslate">chr()</code></a></div> <div class="line"><a class="reference internal" href="#classmethod" title="classmethod"><code class="xref py py-func docutils literal notranslate">classmethod()</code></a></div> <div class="line"><a class="reference internal" href="#compile" title="compile"><code class="xref py py-func docutils literal notranslate">compile()</code></a></div> <div class="line"><a class="reference internal" href="#complex" title="complex"><code class="xref py py-func docutils literal notranslate">complex()</code></a></div> <div class="line"> </div> <div class="line">D</div> <div class="line"><a class="reference internal" href="#delattr" title="delattr"><code class="xref py py-func docutils literal notranslate">delattr()</code></a></div> <div class="line"><a class="reference internal" href="#func-dict"><code class="docutils literal notranslate">dict()</code></a></div> <div class="line"><a class="reference internal" href="#dir" title="dir"><code class="xref py py-func docutils literal notranslate">dir()</code></a></div> <div class="line"><a class="reference internal" href="#divmod" title="divmod"><code class="xref py py-func docutils literal notranslate">divmod()</code></a></div> <div class="line"> </div> </div> </td> <td><div class="line-block"> <div class="line">E</div> <div class="line"><a class="reference internal" href="#enumerate" title="enumerate"><code class="xref py py-func docutils literal notranslate">enumerate()</code></a></div> <div class="line"><a class="reference internal" href="#eval" title="eval"><code class="xref py py-func docutils literal notranslate">eval()</code></a></div> <div class="line"><a class="reference internal" href="#exec" title="exec"><code class="xref py py-func docutils literal notranslate">exec()</code></a></div> <div class="line"> </div> <div class="line">F</div> <div class="line"><a class="reference internal" href="#filter" title="filter"><code class="xref py py-func docutils literal notranslate">filter()</code></a></div> <div class="line"><a class="reference internal" href="#float" title="float"><code class="xref py py-func docutils literal notranslate">float()</code></a></div> <div class="line"><a class="reference internal" href="#format" title="format"><code class="xref py py-func docutils literal notranslate">format()</code></a></div> <div class="line"><a class="reference internal" href="#func-frozenset"><code class="docutils literal notranslate">frozenset()</code></a></div> <div class="line"> </div> <div class="line">G</div> <div class="line"><a class="reference internal" href="#getattr" title="getattr"><code class="xref py py-func docutils literal notranslate">getattr()</code></a></div> <div class="line"><a class="reference internal" href="#globals" title="globals"><code class="xref py py-func docutils literal notranslate">globals()</code></a></div> <div class="line"> </div> <div class="line">H</div> <div class="line"><a class="reference internal" href="#hasattr" title="hasattr"><code class="xref py py-func docutils literal notranslate">hasattr()</code></a></div> <div class="line"><a class="reference internal" href="#hash" title="hash"><code class="xref py py-func docutils literal notranslate">hash()</code></a></div> <div class="line"><a class="reference internal" href="#help" title="help"><code class="xref py py-func docutils literal notranslate">help()</code></a></div> <div class="line"><a class="reference internal" href="#hex" title="hex"><code class="xref py py-func docutils literal notranslate">hex()</code></a></div> <div class="line"> </div> <div class="line">I</div> <div class="line"><a class="reference internal" href="#id" title="id"><code class="xref py py-func docutils literal notranslate">id()</code></a></div> <div class="line"><a class="reference internal" href="#input" title="input"><code class="xref py py-func docutils literal notranslate">input()</code></a></div> <div class="line"><a class="reference internal" href="#int" title="int"><code class="xref py py-func docutils literal notranslate">int()</code></a></div> <div class="line"><a class="reference internal" href="#isinstance" title="isinstance"><code class="xref py py-func docutils literal notranslate">isinstance()</code></a></div> <div class="line"><a class="reference internal" href="#issubclass" title="issubclass"><code class="xref py py-func docutils literal notranslate">issubclass()</code></a></div> <div class="line"><a class="reference internal" href="#iter" title="iter"><code class="xref py py-func docutils literal notranslate">iter()</code></a></div> </div> </td> <td><div class="line-block"> <div class="line">L</div> <div class="line"><a class="reference internal" href="#len" title="len"><code class="xref py py-func docutils literal notranslate">len()</code></a></div> <div class="line"><a class="reference internal" href="#func-list"><code class="docutils literal notranslate">list()</code></a></div> <div class="line"><a class="reference internal" href="#locals" title="locals"><code class="xref py py-func docutils literal notranslate">locals()</code></a></div> <div class="line"> </div> <div class="line">M</div> <div class="line"><a class="reference internal" href="#map" title="map"><code class="xref py py-func docutils literal notranslate">map()</code></a></div> <div class="line"><a class="reference internal" href="#max" title="max"><code class="xref py py-func docutils literal notranslate">max()</code></a></div> <div class="line"><a class="reference internal" href="#func-memoryview"><code class="docutils literal notranslate">memoryview()</code></a></div> <div class="line"><a class="reference internal" href="#min" title="min"><code class="xref py py-func docutils literal notranslate">min()</code></a></div> <div class="line"> </div> <div class="line">N</div> <div class="line"><a class="reference internal" href="#next" title="next"><code class="xref py py-func docutils literal notranslate">next()</code></a></div> <div class="line"> </div> <div class="line">O</div> <div class="line"><a class="reference internal" href="#object" title="object"><code class="xref py py-func docutils literal notranslate">object()</code></a></div> <div class="line"><a class="reference internal" href="#oct" title="oct"><code class="xref py py-func docutils literal notranslate">oct()</code></a></div> <div class="line"><a class="reference internal" href="#open" title="open"><code class="xref py py-func docutils literal notranslate">open()</code></a></div> <div class="line"><a class="reference internal" href="#ord" title="ord"><code class="xref py py-func docutils literal notranslate">ord()</code></a></div> <div class="line"> </div> <div class="line">P</div> <div class="line"><a class="reference internal" href="#pow" title="pow"><code class="xref py py-func docutils literal notranslate">pow()</code></a></div> <div class="line"><a class="reference internal" href="#print" title="print"><code class="xref py py-func docutils literal notranslate">print()</code></a></div> <div class="line"><a class="reference internal" href="#property" title="property"><code class="xref py py-func docutils literal notranslate">property()</code></a></div> <div class="line"> </div> <div class="line"> </div> <div class="line"> </div> <div class="line"> </div> </div> </td> <td><div class="line-block"> <div class="line">R</div> <div class="line"><a class="reference internal" href="#func-range"><code class="docutils literal notranslate">range()</code></a></div> <div class="line"><a class="reference internal" href="#repr" title="repr"><code class="xref py py-func docutils literal notranslate">repr()</code></a></div> <div class="line"><a class="reference internal" href="#reversed" title="reversed"><code class="xref py py-func docutils literal notranslate">reversed()</code></a></div> <div class="line"><a class="reference internal" href="#round" title="round"><code class="xref py py-func docutils literal notranslate">round()</code></a></div> <div class="line"> </div> <div class="line">S</div> <div class="line"><a class="reference internal" href="#func-set"><code class="docutils literal notranslate">set()</code></a></div> <div class="line"><a class="reference internal" href="#setattr" title="setattr"><code class="xref py py-func docutils literal notranslate">setattr()</code></a></div> <div class="line"><a class="reference internal" href="#slice" title="slice"><code class="xref py py-func docutils literal notranslate">slice()</code></a></div> <div class="line"><a class="reference internal" href="#sorted" title="sorted"><code class="xref py py-func docutils literal notranslate">sorted()</code></a></div> <div class="line"><a class="reference internal" href="#staticmethod" title="staticmethod"><code class="xref py py-func docutils literal notranslate">staticmethod()</code></a></div> <div class="line"><a class="reference internal" href="#func-str"><code class="docutils literal notranslate">str()</code></a></div> <div class="line"><a class="reference internal" href="#sum" title="sum"><code class="xref py py-func docutils literal notranslate">sum()</code></a></div> <div class="line"><a class="reference internal" href="#super" title="super"><code class="xref py py-func docutils literal notranslate">super()</code></a></div> <div class="line"> </div> <div class="line">T</div> <div class="line"><a class="reference internal" href="#func-tuple"><code class="docutils literal notranslate">tuple()</code></a></div> <div class="line"><a class="reference internal" href="#type" title="type"><code class="xref py py-func docutils literal notranslate">type()</code></a></div> <div class="line"> </div> <div class="line">V</div> <div class="line"><a class="reference internal" href="#vars" title="vars"><code class="xref py py-func docutils literal notranslate">vars()</code></a></div> <div class="line"> </div> <div class="line">Z</div> <div class="line"><a class="reference internal" href="#zip" title="zip"><code class="xref py py-func docutils literal notranslate">zip()</code></a></div> <div class="line"> </div> <div class="line">_</div> <div class="line"><a class="reference internal" href="#import__" title="__import__"><code class="xref py py-func docutils literal notranslate">__import__()</code></a></div> </div> </td> </tr> </tbody> </table> <dl class="py function"> <dt class="sig sig-object py" id="abs"> abs(x)<a class="headerlink" href="#abs" title="Link to this definition">¶</a></dt> <dd>Return the absolute value of a number. The argument may be an integer, a floating-point number, or an object implementing <a class="reference internal" href="../reference/datamodel.html#object.__abs__" title="object.__abs__"><code class="xref py py-meth docutils literal notranslate">__abs__()</code></a>. If the argument is a complex number, its magnitude is returned. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="aiter"> aiter(async_iterable)<a class="headerlink" href="#aiter" title="Link to this definition">¶</a></dt> <dd>Return an <a class="reference internal" href="../glossary.html#term-asynchronous-iterator">asynchronous iterator</a> for an <a class="reference internal" href="../glossary.html#term-asynchronous-iterable">asynchronous iterable</a>. Equivalent to calling <code class="docutils literal notranslate">x.__aiter__()</code>. Note: Unlike <a class="reference internal" href="#iter" title="iter"><code class="xref py py-func docutils literal notranslate">iter()</code></a>, <a class="reference internal" href="#aiter" title="aiter"><code class="xref py py-func docutils literal notranslate">aiter()</code></a> has no 2-argument variant. <div class="versionadded"> Added in version 3.10. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="all"> all(iterable)<a class="headerlink" href="#all" title="Link to this definition">¶</a></dt> <dd>Return <code class="docutils literal notranslate">True</code> if all elements of the iterable are true (or if the iterable is empty). Equivalent to: <div class="highlight-python3 notranslate"><div class="highlight"><pre>def all(iterable): for element in iterable: if not element: return False return True </pre></div> </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="anext"> awaitable anext(async_iterator)<a class="headerlink" href="#anext" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> awaitable anext(async_iterator, default)</dt> <dd>When awaited, return the next item from the given <a class="reference internal" href="../glossary.html#term-asynchronous-iterator">asynchronous iterator</a>, or default if given and the iterator is exhausted. This is the async variant of the <a class="reference internal" href="#next" title="next"><code class="xref py py-func docutils literal notranslate">next()</code></a> builtin, and behaves similarly. This calls the <a class="reference internal" href="../reference/datamodel.html#object.__anext__" title="object.__anext__"><code class="xref py py-meth docutils literal notranslate">__anext__()</code></a> method of async_iterator, returning an <a class="reference internal" href="../glossary.html#term-awaitable">awaitable</a>. Awaiting this returns the next value of the iterator. If default is given, it is returned if the iterator is exhausted, otherwise <a class="reference internal" href="exceptions.html#StopAsyncIteration" title="StopAsyncIteration"><code class="xref py py-exc docutils literal notranslate">StopAsyncIteration</code></a> is raised. <div class="versionadded"> Added in version 3.10. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="any"> any(iterable)<a class="headerlink" href="#any" title="Link to this definition">¶</a></dt> <dd>Return <code class="docutils literal notranslate">True</code> if any element of the iterable is true. If the iterable is empty, return <code class="docutils literal notranslate">False</code>. Equivalent to: <div class="highlight-python3 notranslate"><div class="highlight"><pre>def any(iterable): for element in iterable: if element: return True return False </pre></div> </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="ascii"> ascii(object)<a class="headerlink" href="#ascii" title="Link to this definition">¶</a></dt> <dd>As <a class="reference internal" href="#repr" title="repr"><code class="xref py py-func docutils literal notranslate">repr()</code></a>, return a string containing a printable representation of an object, but escape the non-ASCII characters in the string returned by <a class="reference internal" href="#repr" title="repr"><code class="xref py py-func docutils literal notranslate">repr()</code></a> using <code class="docutils literal notranslate">\x</code>, <code class="docutils literal notranslate">\u</code>, or <code class="docutils literal notranslate">\U</code> escapes. This generates a string similar to that returned by <a class="reference internal" href="#repr" title="repr"><code class="xref py py-func docutils literal notranslate">repr()</code></a> in Python 2. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="bin"> bin(x)<a class="headerlink" href="#bin" title="Link to this definition">¶</a></dt> <dd>Convert an integer number to a binary string prefixed with “0b”. The result is a valid Python expression. If x is not a Python <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> object, it has to define an <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">__index__()</code></a> method that returns an integer. Some examples: <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> bin(3) '0b11' >>> bin(-10) '-0b1010' </pre></div> </div> If the prefix “0b” is desired or not, you can use either of the following ways. <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> format(14, '#b'), format(14, 'b') ('0b1110', '1110') >>> f'{14:#b}', f'{14:b}' ('0b1110', '1110') </pre></div> </div> See also <a class="reference internal" href="#format" title="format"><code class="xref py py-func docutils literal notranslate">format()</code></a> for more information. </dd></dl> <dl class="py class"> <dt class="sig sig-object py" id="bool"> class bool(object=False, /)<a class="headerlink" href="#bool" title="Link to this definition">¶</a></dt> <dd>Return a Boolean value, i.e. one of <code class="docutils literal notranslate">True</code> or <code class="docutils literal notranslate">False</code>. The argument is converted using the standard <a class="reference internal" href="stdtypes.html#truth">truth testing procedure</a>. If the argument is false or omitted, this returns <code class="docutils literal notranslate">False</code>; otherwise, it returns <code class="docutils literal notranslate">True</code>. The <a class="reference internal" href="#bool" title="bool"><code class="xref py py-class docutils literal notranslate">bool</code></a> class is a subclass of <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> (see <a class="reference internal" href="stdtypes.html#typesnumeric">Numeric Types — int, float, complex</a>). It cannot be subclassed further. Its only instances are <code class="docutils literal notranslate">False</code> and <code class="docutils literal notranslate">True</code> (see <a class="reference internal" href="stdtypes.html#typebool">Boolean Type - bool</a>). <div class="versionchanged" id="index-0"> Changed in version 3.7: The parameter is now positional-only. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="breakpoint"> breakpoint(*args, **kws)<a class="headerlink" href="#breakpoint" title="Link to this definition">¶</a></dt> <dd>This function drops you into the debugger at the call site. Specifically, it calls <a class="reference internal" href="sys.html#sys.breakpointhook" title="sys.breakpointhook"><code class="xref py py-func docutils literal notranslate">sys.breakpointhook()</code></a>, passing <code class="docutils literal notranslate">args</code> and <code class="docutils literal notranslate">kws</code> straight through. By default, <code class="docutils literal notranslate">sys.breakpointhook()</code> calls <a class="reference internal" href="pdb.html#pdb.set_trace" title="pdb.set_trace"><code class="xref py py-func docutils literal notranslate">pdb.set_trace()</code></a> expecting no arguments. In this case, it is purely a convenience function so you don’t have to explicitly import <a class="reference internal" href="pdb.html#module-pdb" title="pdb: The Python debugger for interactive interpreters."><code class="xref py py-mod docutils literal notranslate">pdb</code></a> or type as much code to enter the debugger. However, <a class="reference internal" href="sys.html#sys.breakpointhook" title="sys.breakpointhook"><code class="xref py py-func docutils literal notranslate">sys.breakpointhook()</code></a> can be set to some other function and <a class="reference internal" href="#breakpoint" title="breakpoint"><code class="xref py py-func docutils literal notranslate">breakpoint()</code></a> will automatically call that, allowing you to drop into the debugger of choice. If <a class="reference internal" href="sys.html#sys.breakpointhook" title="sys.breakpointhook"><code class="xref py py-func docutils literal notranslate">sys.breakpointhook()</code></a> is not accessible, this function will raise <a class="reference internal" href="exceptions.html#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate">RuntimeError</code></a>. By default, the behavior of <a class="reference internal" href="#breakpoint" title="breakpoint"><code class="xref py py-func docutils literal notranslate">breakpoint()</code></a> can be changed with the <a class="reference internal" href="../using/cmdline.html#envvar-PYTHONBREAKPOINT"><code class="xref std std-envvar docutils literal notranslate">PYTHONBREAKPOINT</code></a> environment variable. See <a class="reference internal" href="sys.html#sys.breakpointhook" title="sys.breakpointhook"><code class="xref py py-func docutils literal notranslate">sys.breakpointhook()</code></a> for usage details. Note that this is not guaranteed if <a class="reference internal" href="sys.html#sys.breakpointhook" title="sys.breakpointhook"><code class="xref py py-func docutils literal notranslate">sys.breakpointhook()</code></a> has been replaced. Raises an <a class="reference internal" href="sys.html#auditing">auditing event</a> <code class="docutils literal notranslate">builtins.breakpoint</code> with argument <code class="docutils literal notranslate">breakpointhook</code>. <div class="versionadded"> Added in version 3.7. </div> </dd></dl> <dl class="py class" id="func-bytearray"> <dt class="sig sig-object py"> class bytearray(source=b'')</dt> <dt class="sig sig-object py"> class bytearray(source, encoding)</dt> <dt class="sig sig-object py"> class bytearray(source, encoding, errors)</dt> <dd>Return a new array of bytes. The <a class="reference internal" href="stdtypes.html#bytearray" title="bytearray"><code class="xref py py-class docutils literal notranslate">bytearray</code></a> class is a mutable sequence of integers in the range 0 <= x < 256. It has most of the usual methods of mutable sequences, described in <a class="reference internal" href="stdtypes.html#typesseq-mutable">Mutable Sequence Types</a>, as well as most methods that the <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate">bytes</code></a> type has, see <a class="reference internal" href="stdtypes.html#bytes-methods">Bytes and Bytearray Operations</a>. The optional source parameter can be used to initialize the array in a few different ways: <ul class="simple"> <li>If it is a string, you must also give the encoding (and optionally, errors) parameters; <a class="reference internal" href="stdtypes.html#bytearray" title="bytearray"><code class="xref py py-func docutils literal notranslate">bytearray()</code></a> then converts the string to bytes using <a class="reference internal" href="stdtypes.html#str.encode" title="str.encode"><code class="xref py py-meth docutils literal notranslate">str.encode()</code></a>.</li> <li>If it is an integer, the array will have that size and will be initialized with null bytes.</li> <li>If it is an object conforming to the <a class="reference internal" href="../c-api/buffer.html#bufferobjects">buffer interface</a>, a read-only buffer of the object will be used to initialize the bytes array.</li> <li>If it is an iterable, it must be an iterable of integers in the range <code class="docutils literal notranslate">0 <= x < 256</code>, which are used as the initial contents of the array.</li> </ul> Without an argument, an array of size 0 is created. See also <a class="reference internal" href="stdtypes.html#binaryseq">Binary Sequence Types — bytes, bytearray, memoryview</a> and <a class="reference internal" href="stdtypes.html#typebytearray">Bytearray Objects</a>. </dd></dl> <dl class="py class" id="func-bytes"> <dt class="sig sig-object py"> class bytes(source=b'')</dt> <dt class="sig sig-object py"> class bytes(source, encoding)</dt> <dt class="sig sig-object py"> class bytes(source, encoding, errors)</dt> <dd>Return a new “bytes” object which is an immutable sequence of integers in the range <code class="docutils literal notranslate">0 <= x < 256</code>. <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate">bytes</code></a> is an immutable version of <a class="reference internal" href="stdtypes.html#bytearray" title="bytearray"><code class="xref py py-class docutils literal notranslate">bytearray</code></a> – it has the same non-mutating methods and the same indexing and slicing behavior. Accordingly, constructor arguments are interpreted as for <a class="reference internal" href="stdtypes.html#bytearray" title="bytearray"><code class="xref py py-func docutils literal notranslate">bytearray()</code></a>. Bytes objects can also be created with literals, see <a class="reference internal" href="../reference/lexical_analysis.html#strings">String and Bytes literals</a>. See also <a class="reference internal" href="stdtypes.html#binaryseq">Binary Sequence Types — bytes, bytearray, memoryview</a>, <a class="reference internal" href="stdtypes.html#typebytes">Bytes Objects</a>, and <a class="reference internal" href="stdtypes.html#bytes-methods">Bytes and Bytearray Operations</a>. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="callable"> callable(object)<a class="headerlink" href="#callable" title="Link to this definition">¶</a></dt> <dd>Return <a class="reference internal" href="constants.html#True" title="True"><code class="xref py py-const docutils literal notranslate">True</code></a> if the object argument appears callable, <a class="reference internal" href="constants.html#False" title="False"><code class="xref py py-const docutils literal notranslate">False</code></a> if not. If this returns <code class="docutils literal notranslate">True</code>, it is still possible that a call fails, but if it is <code class="docutils literal notranslate">False</code>, calling object will never succeed. Note that classes are callable (calling a class returns a new instance); instances are callable if their class has a <a class="reference internal" href="../reference/datamodel.html#object.__call__" title="object.__call__"><code class="xref py py-meth docutils literal notranslate">__call__()</code></a> method. <div class="versionadded"> Added in version 3.2: This function was first removed in Python 3.0 and then brought back in Python 3.2. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="chr"> chr(i)<a class="headerlink" href="#chr" title="Link to this definition">¶</a></dt> <dd>Return the string representing a character whose Unicode code point is the integer i. For example, <code class="docutils literal notranslate">chr(97)</code> returns the string <code class="docutils literal notranslate">'a'</code>, while <code class="docutils literal notranslate">chr(8364)</code> returns the string <code class="docutils literal notranslate">'€'</code>. This is the inverse of <a class="reference internal" href="#ord" title="ord"><code class="xref py py-func docutils literal notranslate">ord()</code></a>. The valid range for the argument is from 0 through 1,114,111 (0x10FFFF in base 16). <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate">ValueError</code></a> will be raised if i is outside that range. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="classmethod"> @classmethod<a class="headerlink" href="#classmethod" title="Link to this definition">¶</a></dt> <dd>Transform a method into a class method. A class method receives the class as an implicit first argument, just like an instance method receives the instance. To declare a class method, use this idiom: <div class="highlight-python3 notranslate"><div class="highlight"><pre>class C: @classmethod def f(cls, arg1, arg2): ... </pre></div> </div> The <code class="docutils literal notranslate">@classmethod</code> form is a function <a class="reference internal" href="../glossary.html#term-decorator">decorator</a> – see <a class="reference internal" href="../reference/compound_stmts.html#function">Function definitions</a> for details. A class method can be called either on the class (such as <code class="docutils literal notranslate">C.f()</code>) or on an instance (such as <code class="docutils literal notranslate">C().f()</code>). The instance is ignored except for its class. If a class method is called for a derived class, the derived class object is passed as the implied first argument. Class methods are different than C++ or Java static methods. If you want those, see <a class="reference internal" href="#staticmethod" title="staticmethod"><code class="xref py py-func docutils literal notranslate">staticmethod()</code></a> in this section. For more information on class methods, see <a class="reference internal" href="../reference/datamodel.html#types">The standard type hierarchy</a>. <div class="versionchanged"> Changed in version 3.9: Class methods can now wrap other <a class="reference internal" href="../glossary.html#term-descriptor">descriptors</a> such as <a class="reference internal" href="#property" title="property"><code class="xref py py-func docutils literal notranslate">property()</code></a>. </div> <div class="versionchanged"> Changed in version 3.10: Class methods now inherit the method attributes (<a class="reference internal" href="../reference/datamodel.html#function.__module__" title="function.__module__"><code class="xref py py-attr docutils literal notranslate">__module__</code></a>, <a class="reference internal" href="../reference/datamodel.html#function.__name__" title="function.__name__"><code class="xref py py-attr docutils literal notranslate">__name__</code></a>, <a class="reference internal" href="../reference/datamodel.html#function.__qualname__" title="function.__qualname__"><code class="xref py py-attr docutils literal notranslate">__qualname__</code></a>, <a class="reference internal" href="../reference/datamodel.html#function.__doc__" title="function.__doc__"><code class="xref py py-attr docutils literal notranslate">__doc__</code></a> and <a class="reference internal" href="../reference/datamodel.html#function.__annotations__" title="function.__annotations__"><code class="xref py py-attr docutils literal notranslate">__annotations__</code></a>) and have a new <code class="docutils literal notranslate">__wrapped__</code> attribute. </div> <div class="deprecated-removed"> Deprecated since version 3.11, removed in version 3.13: Class methods can no longer wrap other <a class="reference internal" href="../glossary.html#term-descriptor">descriptors</a> such as <a class="reference internal" href="#property" title="property"><code class="xref py py-func docutils literal notranslate">property()</code></a>. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="compile"> compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1)<a class="headerlink" href="#compile" title="Link to this definition">¶</a></dt> <dd>Compile the source into a code or AST object. Code objects can be executed by <a class="reference internal" href="#exec" title="exec"><code class="xref py py-func docutils literal notranslate">exec()</code></a> or <a class="reference internal" href="#eval" title="eval"><code class="xref py py-func docutils literal notranslate">eval()</code></a>. source can either be a normal string, a byte string, or an AST object. Refer to the <a class="reference internal" href="ast.html#module-ast" title="ast: Abstract Syntax Tree classes and manipulation."><code class="xref py py-mod docutils literal notranslate">ast</code></a> module documentation for information on how to work with AST objects. The filename argument should give the file from which the code was read; pass some recognizable value if it wasn’t read from a file (<code class="docutils literal notranslate">'<string>'</code> is commonly used). The mode argument specifies what kind of code must be compiled; it can be <code class="docutils literal notranslate">'exec'</code> if source consists of a sequence of statements, <code class="docutils literal notranslate">'eval'</code> if it consists of a single expression, or <code class="docutils literal notranslate">'single'</code> if it consists of a single interactive statement (in the latter case, expression statements that evaluate to something other than <code class="docutils literal notranslate">None</code> will be printed). The optional arguments flags and dont_inherit control which <a class="reference internal" href="ast.html#ast-compiler-flags">compiler options</a> should be activated and which <a class="reference internal" href="../reference/simple_stmts.html#future">future features</a> should be allowed. If neither is present (or both are zero) the code is compiled with the same flags that affect the code that is calling <a class="reference internal" href="#compile" title="compile"><code class="xref py py-func docutils literal notranslate">compile()</code></a>. If the flags argument is given and dont_inherit is not (or is zero) then the compiler options and the future statements specified by the flags argument are used in addition to those that would be used anyway. If dont_inherit is a non-zero integer then the flags argument is it – the flags (future features and compiler options) in the surrounding code are ignored. Compiler options and future statements are specified by bits which can be bitwise ORed together to specify multiple options. The bitfield required to specify a given future feature can be found as the <a class="reference internal" href="__future__.html#future__._Feature.compiler_flag" title="__future__._Feature.compiler_flag"><code class="xref py py-attr docutils literal notranslate">compiler_flag</code></a> attribute on the <a class="reference internal" href="__future__.html#future__._Feature" title="__future__._Feature"><code class="xref py py-class docutils literal notranslate">_Feature</code></a> instance in the <a class="reference internal" href="__future__.html#module-__future__" title="__future__: Future statement definitions"><code class="xref py py-mod docutils literal notranslate">__future__</code></a> module. <a class="reference internal" href="ast.html#ast-compiler-flags">Compiler flags</a> can be found in <a class="reference internal" href="ast.html#module-ast" title="ast: Abstract Syntax Tree classes and manipulation."><code class="xref py py-mod docutils literal notranslate">ast</code></a> module, with <code class="docutils literal notranslate">PyCF_</code> prefix. The argument optimize specifies the optimization level of the compiler; the default value of <code class="docutils literal notranslate">-1</code> selects the optimization level of the interpreter as given by <a class="reference internal" href="../using/cmdline.html#cmdoption-O"><code class="xref std std-option docutils literal notranslate">-O</code></a> options. Explicit levels are <code class="docutils literal notranslate">0</code> (no optimization; <code class="docutils literal notranslate">__debug__</code> is true), <code class="docutils literal notranslate">1</code> (asserts are removed, <code class="docutils literal notranslate">__debug__</code> is false) or <code class="docutils literal notranslate">2</code> (docstrings are removed too). This function raises <a class="reference internal" href="exceptions.html#SyntaxError" title="SyntaxError"><code class="xref py py-exc docutils literal notranslate">SyntaxError</code></a> if the compiled source is invalid, and <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate">ValueError</code></a> if the source contains null bytes. If you want to parse Python code into its AST representation, see <a class="reference internal" href="ast.html#ast.parse" title="ast.parse"><code class="xref py py-func docutils literal notranslate">ast.parse()</code></a>. Raises an <a class="reference internal" href="sys.html#auditing">auditing event</a> <code class="docutils literal notranslate">compile</code> with arguments <code class="docutils literal notranslate">source</code> and <code class="docutils literal notranslate">filename</code>. This event may also be raised by implicit compilation. <div class="admonition note"> Note When compiling a string with multi-line code in <code class="docutils literal notranslate">'single'</code> or <code class="docutils literal notranslate">'eval'</code> mode, input must be terminated by at least one newline character. This is to facilitate detection of incomplete and complete statements in the <a class="reference internal" href="code.html#module-code" title="code: Facilities to implement read-eval-print loops."><code class="xref py py-mod docutils literal notranslate">code</code></a> module. </div> <div class="admonition warning"> Warning It is possible to crash the Python interpreter with a sufficiently large/complex string when compiling to an AST object due to stack depth limitations in Python’s AST compiler. </div> <div class="versionchanged"> Changed in version 3.2: Allowed use of Windows and Mac newlines. Also, input in <code class="docutils literal notranslate">'exec'</code> mode does not have to end in a newline anymore. Added the optimize parameter. </div> <div class="versionchanged"> Changed in version 3.5: Previously, <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> was raised when null bytes were encountered in source. </div> <div class="versionadded"> Added in version 3.8: <code class="docutils literal notranslate">ast.PyCF_ALLOW_TOP_LEVEL_AWAIT</code> can now be passed in flags to enable support for top-level <code class="docutils literal notranslate">await</code>, <code class="docutils literal notranslate">async for</code>, and <code class="docutils literal notranslate">async with</code>. </div> </dd></dl> <dl class="py class"> <dt class="sig sig-object py" id="complex"> class complex(number=0, /)<a class="headerlink" href="#complex" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> class complex(string, /)</dt> <dt class="sig sig-object py"> class complex(real=0, imag=0)</dt> <dd>Convert a single string or number to a complex number, or create a complex number from real and imaginary parts. Examples: <div class="highlight-pycon notranslate"><div class="highlight"><pre>>>> complex('+1.23') (1.23+0j) >>> complex('-4.5j') -4.5j >>> complex('-1.23+4.5j') (-1.23+4.5j) >>> complex('\t( -1.23+4.5J )\n') (-1.23+4.5j) >>> complex('-Infinity+NaNj') (-inf+nanj) >>> complex(1.23) (1.23+0j) >>> complex(imag=-4.5) -4.5j >>> complex(-1.23, 4.5) (-1.23+4.5j) </pre></div> </div> If the argument is a string, it must contain either a real part (in the same format as for <a class="reference internal" href="#float" title="float"><code class="xref py py-func docutils literal notranslate">float()</code></a>) or an imaginary part (in the same format but with a <code class="docutils literal notranslate">'j'</code> or <code class="docutils literal notranslate">'J'</code> suffix), or both real and imaginary parts (the sign of the imaginary part is mandatory in this case). The string can optionally be surrounded by whitespaces and the round parentheses <code class="docutils literal notranslate">'('</code> and <code class="docutils literal notranslate">')'</code>, which are ignored. The string must not contain whitespace between <code class="docutils literal notranslate">'+'</code>, <code class="docutils literal notranslate">'-'</code>, the <code class="docutils literal notranslate">'j'</code> or <code class="docutils literal notranslate">'J'</code> suffix, and the decimal number. For example, <code class="docutils literal notranslate">complex('1+2j')</code> is fine, but <code class="docutils literal notranslate">complex('1 + 2j')</code> raises <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate">ValueError</code></a>. More precisely, the input must conform to the <a class="reference internal" href="#grammar-token-float-complexvalue"><code class="xref std std-token docutils literal notranslate">complexvalue</code></a> production rule in the following grammar, after parentheses and leading and trailing whitespace characters are removed: <pre> complexvalue ::= <a class="reference internal" href="#grammar-token-float-floatvalue"><code class="xref docutils literal notranslate">floatvalue</code></a> | <a class="reference internal" href="#grammar-token-float-floatvalue"><code class="xref docutils literal notranslate">floatvalue</code></a> ("j" | "J") | <a class="reference internal" href="#grammar-token-float-floatvalue"><code class="xref docutils literal notranslate">floatvalue</code></a> <a class="reference internal" href="#grammar-token-float-sign"><code class="xref docutils literal notranslate">sign</code></a> <a class="reference internal" href="#grammar-token-float-absfloatvalue"><code class="xref docutils literal notranslate">absfloatvalue</code></a> ("j" | "J") </pre> If the argument is a number, the constructor serves as a numeric conversion like <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> and <a class="reference internal" href="#float" title="float"><code class="xref py py-class docutils literal notranslate">float</code></a>. For a general Python object <code class="docutils literal notranslate">x</code>, <code class="docutils literal notranslate">complex(x)</code> delegates to <code class="docutils literal notranslate">x.__complex__()</code>. If <a class="reference internal" href="../reference/datamodel.html#object.__complex__" title="object.__complex__"><code class="xref py py-meth docutils literal notranslate">__complex__()</code></a> is not defined then it falls back to <a class="reference internal" href="../reference/datamodel.html#object.__float__" title="object.__float__"><code class="xref py py-meth docutils literal notranslate">__float__()</code></a>. If <code class="xref py py-meth docutils literal notranslate">__float__()</code> is not defined then it falls back to <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">__index__()</code></a>. If two arguments are provided or keyword arguments are used, each argument may be any numeric type (including complex). If both arguments are real numbers, return a complex number with the real component real and the imaginary component imag. If both arguments are complex numbers, return a complex number with the real component <code class="docutils literal notranslate">real.real-imag.imag</code> and the imaginary component <code class="docutils literal notranslate">real.imag+imag.real</code>. If one of arguments is a real number, only its real component is used in the above expressions. If all arguments are omitted, returns <code class="docutils literal notranslate">0j</code>. The complex type is described in <a class="reference internal" href="stdtypes.html#typesnumeric">Numeric Types — int, float, complex</a>. <div class="versionchanged"> Changed in version 3.6: Grouping digits with underscores as in code literals is allowed. </div> <div class="versionchanged"> Changed in version 3.8: Falls back to <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">__index__()</code></a> if <a class="reference internal" href="../reference/datamodel.html#object.__complex__" title="object.__complex__"><code class="xref py py-meth docutils literal notranslate">__complex__()</code></a> and <a class="reference internal" href="../reference/datamodel.html#object.__float__" title="object.__float__"><code class="xref py py-meth docutils literal notranslate">__float__()</code></a> are not defined. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="delattr"> delattr(object, name)<a class="headerlink" href="#delattr" title="Link to this definition">¶</a></dt> <dd>This is a relative of <a class="reference internal" href="#setattr" title="setattr"><code class="xref py py-func docutils literal notranslate">setattr()</code></a>. The arguments are an object and a string. The string must be the name of one of the object’s attributes. The function deletes the named attribute, provided the object allows it. For example, <code class="docutils literal notranslate">delattr(x, 'foobar')</code> is equivalent to <code class="docutils literal notranslate">del x.foobar</code>. name need not be a Python identifier (see <a class="reference internal" href="#setattr" title="setattr"><code class="xref py py-func docutils literal notranslate">setattr()</code></a>). </dd></dl> <dl class="py class" id="func-dict"> <dt class="sig sig-object py"> class dict(**kwarg)</dt> <dt class="sig sig-object py"> class dict(mapping, **kwarg)</dt> <dt class="sig sig-object py"> class dict(iterable, **kwarg)</dt> <dd>Create a new dictionary. The <a class="reference internal" href="stdtypes.html#dict" title="dict"><code class="xref py py-class docutils literal notranslate">dict</code></a> object is the dictionary class. See <a class="reference internal" href="stdtypes.html#dict" title="dict"><code class="xref py py-class docutils literal notranslate">dict</code></a> and <a class="reference internal" href="stdtypes.html#typesmapping">Mapping Types — dict</a> for documentation about this class. For other containers see the built-in <a class="reference internal" href="stdtypes.html#list" title="list"><code class="xref py py-class docutils literal notranslate">list</code></a>, <a class="reference internal" href="stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate">set</code></a>, and <a class="reference internal" href="stdtypes.html#tuple" title="tuple"><code class="xref py py-class docutils literal notranslate">tuple</code></a> classes, as well as the <a class="reference internal" href="collections.html#module-collections" title="collections: Container datatypes"><code class="xref py py-mod docutils literal notranslate">collections</code></a> module. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="dir"> dir()<a class="headerlink" href="#dir" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> dir(object)</dt> <dd>Without arguments, return the list of names in the current local scope. With an argument, attempt to return a list of valid attributes for that object. If the object has a method named <a class="reference internal" href="../reference/datamodel.html#object.__dir__" title="object.__dir__"><code class="xref py py-meth docutils literal notranslate">__dir__()</code></a>, this method will be called and must return the list of attributes. This allows objects that implement a custom <a class="reference internal" href="../reference/datamodel.html#object.__getattr__" title="object.__getattr__"><code class="xref py py-func docutils literal notranslate">__getattr__()</code></a> or <a class="reference internal" href="../reference/datamodel.html#object.__getattribute__" title="object.__getattribute__"><code class="xref py py-func docutils literal notranslate">__getattribute__()</code></a> function to customize the way <a class="reference internal" href="#dir" title="dir"><code class="xref py py-func docutils literal notranslate">dir()</code></a> reports their attributes. If the object does not provide <a class="reference internal" href="../reference/datamodel.html#object.__dir__" title="object.__dir__"><code class="xref py py-meth docutils literal notranslate">__dir__()</code></a>, the function tries its best to gather information from the object’s <a class="reference internal" href="../reference/datamodel.html#object.__dict__" title="object.__dict__"><code class="xref py py-attr docutils literal notranslate">__dict__</code></a> attribute, if defined, and from its type object. The resulting list is not necessarily complete and may be inaccurate when the object has a custom <a class="reference internal" href="../reference/datamodel.html#object.__getattr__" title="object.__getattr__"><code class="xref py py-func docutils literal notranslate">__getattr__()</code></a>. The default <a class="reference internal" href="#dir" title="dir"><code class="xref py py-func docutils literal notranslate">dir()</code></a> mechanism behaves differently with different types of objects, as it attempts to produce the most relevant, rather than complete, information: <ul class="simple"> <li>If the object is a module object, the list contains the names of the module’s attributes.</li> <li>If the object is a type or class object, the list contains the names of its attributes, and recursively of the attributes of its bases.</li> <li>Otherwise, the list contains the object’s attributes’ names, the names of its class’s attributes, and recursively of the attributes of its class’s base classes.</li> </ul> The resulting list is sorted alphabetically. For example: <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> import struct >>> dir() # show the names in the module namespace ['__builtins__', '__name__', 'struct'] >>> dir(struct) # show the names in the struct module ['Struct', '__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__initializing__', '__loader__', '__name__', '__package__', '_clearcache', 'calcsize', 'error', 'pack', 'pack_into', 'unpack', 'unpack_from'] >>> class Shape: ... def __dir__(self): ... return ['area', 'perimeter', 'location'] ... >>> s = Shape() >>> dir(s) ['area', 'location', 'perimeter'] </pre></div> </div> <div class="admonition note"> Note Because <a class="reference internal" href="#dir" title="dir"><code class="xref py py-func docutils literal notranslate">dir()</code></a> is supplied primarily as a convenience for use at an interactive prompt, it tries to supply an interesting set of names more than it tries to supply a rigorously or consistently defined set of names, and its detailed behavior may change across releases. For example, metaclass attributes are not in the result list when the argument is a class. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="divmod"> divmod(a, b)<a class="headerlink" href="#divmod" title="Link to this definition">¶</a></dt> <dd>Take two (non-complex) numbers as arguments and return a pair of numbers consisting of their quotient and remainder when using integer division. With mixed operand types, the rules for binary arithmetic operators apply. For integers, the result is the same as <code class="docutils literal notranslate">(a // b, a % b)</code>. For floating-point numbers the result is <code class="docutils literal notranslate">(q, a % b)</code>, where q is usually <code class="docutils literal notranslate">math.floor(a / b)</code> but may be 1 less than that. In any case <code class="docutils literal notranslate">q * b + a % b</code> is very close to a, if <code class="docutils literal notranslate">a % b</code> is non-zero it has the same sign as b, and <code class="docutils literal notranslate">0 <= abs(a % b) < abs(b)</code>. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="enumerate"> enumerate(iterable, start=0)<a class="headerlink" href="#enumerate" title="Link to this definition">¶</a></dt> <dd>Return an enumerate object. iterable must be a sequence, an <a class="reference internal" href="../glossary.html#term-iterator">iterator</a>, or some other object which supports iteration. The <a class="reference internal" href="stdtypes.html#iterator.__next__" title="iterator.__next__"><code class="xref py py-meth docutils literal notranslate">__next__()</code></a> method of the iterator returned by <a class="reference internal" href="#enumerate" title="enumerate"><code class="xref py py-func docutils literal notranslate">enumerate()</code></a> returns a tuple containing a count (from start which defaults to 0) and the values obtained from iterating over iterable. <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> seasons = ['Spring', 'Summer', 'Fall', 'Winter'] >>> list(enumerate(seasons)) [(0, 'Spring'), (1, 'Summer'), (2, 'Fall'), (3, 'Winter')] >>> list(enumerate(seasons, start=1)) [(1, 'Spring'), (2, 'Summer'), (3, 'Fall'), (4, 'Winter')] </pre></div> </div> Equivalent to: <div class="highlight-python3 notranslate"><div class="highlight"><pre>def enumerate(iterable, start=0): n = start for elem in iterable: yield n, elem n += 1 </pre></div> </div> </dd></dl> <dl class="py function" id="func-eval"> <dt class="sig sig-object py" id="eval"> eval(source, /, globals=None, locals=None)<a class="headerlink" href="#eval" title="Link to this definition">¶</a></dt> <dd><dl class="field-list simple"> <dt class="field-odd">Parameters:</dt> <dd class="field-odd"><ul class="simple"> <li>source (<a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-class docutils literal notranslate">str</code></a> | <a class="reference internal" href="../reference/datamodel.html#code-objects">code object</a>) – A Python expression.</li> <li>globals (<a class="reference internal" href="stdtypes.html#dict" title="dict"><code class="xref py py-class docutils literal notranslate">dict</code></a> | <code class="docutils literal notranslate">None</code>) – The global namespace (default: <code class="docutils literal notranslate">None</code>).</li> <li>locals (<a class="reference internal" href="../glossary.html#term-mapping">mapping</a> | <code class="docutils literal notranslate">None</code>) – The local namespace (default: <code class="docutils literal notranslate">None</code>).</li> </ul> </dd> <dt class="field-even">Returns:</dt> <dd class="field-even">The result of the evaluated expression. </dd> <dt class="field-odd">Raises:</dt> <dd class="field-odd">Syntax errors are reported as exceptions. </dd> </dl> <div class="admonition warning"> Warning This function executes arbitrary code. Calling it with user-supplied input may lead to security vulnerabilities. </div> The expression argument is parsed and evaluated as a Python expression (technically speaking, a condition list) using the globals and locals mappings as global and local namespace. If the globals dictionary is present and does not contain a value for the key <code class="docutils literal notranslate">__builtins__</code>, a reference to the dictionary of the built-in module <a class="reference internal" href="builtins.html#module-builtins" title="builtins: The module that provides the built-in namespace."><code class="xref py py-mod docutils literal notranslate">builtins</code></a> is inserted under that key before expression is parsed. That way you can control what builtins are available to the executed code by inserting your own <code class="docutils literal notranslate">__builtins__</code> dictionary into globals before passing it to <a class="reference internal" href="#eval" title="eval"><code class="xref py py-func docutils literal notranslate">eval()</code></a>. If the locals mapping is omitted it defaults to the globals dictionary. If both mappings are omitted, the expression is executed with the globals and locals in the environment where <a class="reference internal" href="#eval" title="eval"><code class="xref py py-func docutils literal notranslate">eval()</code></a> is called. Note, eval() will only have access to the <a class="reference internal" href="../glossary.html#term-nested-scope">nested scopes</a> (non-locals) in the enclosing environment if they are already referenced in the scope that is calling <a class="reference internal" href="#eval" title="eval"><code class="xref py py-func docutils literal notranslate">eval()</code></a> (e.g. via a <a class="reference internal" href="../reference/simple_stmts.html#nonlocal"><code class="xref std std-keyword docutils literal notranslate">nonlocal</code></a> statement). Example: <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> x = 1 >>> eval('x+1') 2 </pre></div> </div> This function can also be used to execute arbitrary code objects (such as those created by <a class="reference internal" href="#compile" title="compile"><code class="xref py py-func docutils literal notranslate">compile()</code></a>). In this case, pass a code object instead of a string. If the code object has been compiled with <code class="docutils literal notranslate">'exec'</code> as the mode argument, <a class="reference internal" href="#eval" title="eval"><code class="xref py py-func docutils literal notranslate">eval()</code></a>'s return value will be <code class="docutils literal notranslate">None</code>. Hints: dynamic execution of statements is supported by the <a class="reference internal" href="#exec" title="exec"><code class="xref py py-func docutils literal notranslate">exec()</code></a> function. The <a class="reference internal" href="#globals" title="globals"><code class="xref py py-func docutils literal notranslate">globals()</code></a> and <a class="reference internal" href="#locals" title="locals"><code class="xref py py-func docutils literal notranslate">locals()</code></a> functions return the current global and local dictionary, respectively, which may be useful to pass around for use by <a class="reference internal" href="#eval" title="eval"><code class="xref py py-func docutils literal notranslate">eval()</code></a> or <a class="reference internal" href="#exec" title="exec"><code class="xref py py-func docutils literal notranslate">exec()</code></a>. If the given source is a string, then leading and trailing spaces and tabs are stripped. See <a class="reference internal" href="ast.html#ast.literal_eval" title="ast.literal_eval"><code class="xref py py-func docutils literal notranslate">ast.literal_eval()</code></a> for a function that can safely evaluate strings with expressions containing only literals. Raises an <a class="reference internal" href="sys.html#auditing">auditing event</a> <code class="docutils literal notranslate">exec</code> with the code object as the argument. Code compilation events may also be raised. <div class="versionchanged"> Changed in version 3.13: The globals and locals arguments can now be passed as keywords. </div> <div class="versionchanged"> Changed in version 3.13: The semantics of the default locals namespace have been adjusted as described for the <a class="reference internal" href="#locals" title="locals"><code class="xref py py-func docutils literal notranslate">locals()</code></a> builtin. </div> </dd></dl> <dl class="py function" id="index-2"> <dt class="sig sig-object py" id="exec"> exec(source, /, globals=None, locals=None, *, closure=None)<a class="headerlink" href="#exec" title="Link to this definition">¶</a></dt> <dd><div class="admonition warning"> Warning This function executes arbitrary code. Calling it with user-supplied input may lead to security vulnerabilities. </div> This function supports dynamic execution of Python code. source must be either a string or a code object. If it is a string, the string is parsed as a suite of Python statements which is then executed (unless a syntax error occurs). <a class="footnote-reference brackets" href="#id2" id="id1" role="doc-noteref">[1]</a> If it is a code object, it is simply executed. In all cases, the code that’s executed is expected to be valid as file input (see the section <a class="reference internal" href="../reference/toplevel_components.html#file-input">File input</a> in the Reference Manual). Be aware that the <a class="reference internal" href="../reference/simple_stmts.html#nonlocal"><code class="xref std std-keyword docutils literal notranslate">nonlocal</code></a>, <a class="reference internal" href="../reference/simple_stmts.html#yield"><code class="xref std std-keyword docutils literal notranslate">yield</code></a>, and <a class="reference internal" href="../reference/simple_stmts.html#return"><code class="xref std std-keyword docutils literal notranslate">return</code></a> statements may not be used outside of function definitions even within the context of code passed to the <a class="reference internal" href="#exec" title="exec"><code class="xref py py-func docutils literal notranslate">exec()</code></a> function. The return value is <code class="docutils literal notranslate">None</code>. In all cases, if the optional parts are omitted, the code is executed in the current scope. If only globals is provided, it must be a dictionary (and not a subclass of dictionary), which will be used for both the global and the local variables. If globals and locals are given, they are used for the global and local variables, respectively. If provided, locals can be any mapping object. Remember that at the module level, globals and locals are the same dictionary. <div class="admonition note"> Note When <code class="docutils literal notranslate">exec</code> gets two separate objects as globals and locals, the code will be executed as if it were embedded in a class definition. This means functions and classes defined in the executed code will not be able to access variables assigned at the top level (as the “top level” variables are treated as class variables in a class definition). </div> If the globals dictionary does not contain a value for the key <code class="docutils literal notranslate">__builtins__</code>, a reference to the dictionary of the built-in module <a class="reference internal" href="builtins.html#module-builtins" title="builtins: The module that provides the built-in namespace."><code class="xref py py-mod docutils literal notranslate">builtins</code></a> is inserted under that key. That way you can control what builtins are available to the executed code by inserting your own <code class="docutils literal notranslate">__builtins__</code> dictionary into globals before passing it to <a class="reference internal" href="#exec" title="exec"><code class="xref py py-func docutils literal notranslate">exec()</code></a>. The closure argument specifies a closure–a tuple of cellvars. It’s only valid when the object is a code object containing <a class="reference internal" href="../glossary.html#term-closure-variable">free (closure) variables</a>. The length of the tuple must exactly match the length of the code object’s <a class="reference internal" href="../reference/datamodel.html#codeobject.co_freevars" title="codeobject.co_freevars"><code class="xref py py-attr docutils literal notranslate">co_freevars</code></a> attribute. Raises an <a class="reference internal" href="sys.html#auditing">auditing event</a> <code class="docutils literal notranslate">exec</code> with the code object as the argument. Code compilation events may also be raised. <div class="admonition note"> Note The built-in functions <a class="reference internal" href="#globals" title="globals"><code class="xref py py-func docutils literal notranslate">globals()</code></a> and <a class="reference internal" href="#locals" title="locals"><code class="xref py py-func docutils literal notranslate">locals()</code></a> return the current global and local namespace, respectively, which may be useful to pass around for use as the second and third argument to <a class="reference internal" href="#exec" title="exec"><code class="xref py py-func docutils literal notranslate">exec()</code></a>. </div> <div class="admonition note"> Note The default locals act as described for function <a class="reference internal" href="#locals" title="locals"><code class="xref py py-func docutils literal notranslate">locals()</code></a> below. Pass an explicit locals dictionary if you need to see effects of the code on locals after function <a class="reference internal" href="#exec" title="exec"><code class="xref py py-func docutils literal notranslate">exec()</code></a> returns. </div> <div class="versionchanged"> Changed in version 3.11: Added the closure parameter. </div> <div class="versionchanged"> Changed in version 3.13: The globals and locals arguments can now be passed as keywords. </div> <div class="versionchanged"> Changed in version 3.13: The semantics of the default locals namespace have been adjusted as described for the <a class="reference internal" href="#locals" title="locals"><code class="xref py py-func docutils literal notranslate">locals()</code></a> builtin. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="filter"> filter(function, iterable)<a class="headerlink" href="#filter" title="Link to this definition">¶</a></dt> <dd>Construct an iterator from those elements of iterable for which function is true. iterable may be either a sequence, a container which supports iteration, or an iterator. If function is <code class="docutils literal notranslate">None</code>, the identity function is assumed, that is, all elements of iterable that are false are removed. Note that <code class="docutils literal notranslate">filter(function, iterable)</code> is equivalent to the generator expression <code class="docutils literal notranslate">(item for item in iterable if function(item))</code> if function is not <code class="docutils literal notranslate">None</code> and <code class="docutils literal notranslate">(item for item in iterable if item)</code> if function is <code class="docutils literal notranslate">None</code>. See <a class="reference internal" href="itertools.html#itertools.filterfalse" title="itertools.filterfalse"><code class="xref py py-func docutils literal notranslate">itertools.filterfalse()</code></a> for the complementary function that returns elements of iterable for which function is false. </dd></dl> <dl class="py class"> <dt class="sig sig-object py" id="float"> class float(number=0.0, /)<a class="headerlink" href="#float" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> class float(string, /)</dt> <dd>Return a floating-point number constructed from a number or a string. Examples: <div class="highlight-pycon notranslate"><div class="highlight"><pre>>>> float('+1.23') 1.23 >>> float(' -12345\n') -12345.0 >>> float('1e-003') 0.001 >>> float('+1E6') 1000000.0 >>> float('-Infinity') -inf </pre></div> </div> If the argument is a string, it should contain a decimal number, optionally preceded by a sign, and optionally embedded in whitespace. The optional sign may be <code class="docutils literal notranslate">'+'</code> or <code class="docutils literal notranslate">'-'</code>; a <code class="docutils literal notranslate">'+'</code> sign has no effect on the value produced. The argument may also be a string representing a NaN (not-a-number), or positive or negative infinity. More precisely, the input must conform to the <a class="reference internal" href="#grammar-token-float-floatvalue"><code class="xref std std-token docutils literal notranslate">floatvalue</code></a> production rule in the following grammar, after leading and trailing whitespace characters are removed: <pre> sign ::= "+" | "-" infinity ::= "Infinity" | "inf" nan ::= "nan" digit ::= <a Unicode decimal digit, i.e. characters in Unicode general category Nd> digitpart ::= <a class="reference internal" href="#grammar-token-float-digit"><code class="xref docutils literal notranslate">digit</code></a> (["_"] <a class="reference internal" href="#grammar-token-float-digit"><code class="xref docutils literal notranslate">digit</code></a>)* number ::= [<a class="reference internal" href="#grammar-token-float-digitpart"><code class="xref docutils literal notranslate">digitpart</code></a>] "." <a class="reference internal" href="#grammar-token-float-digitpart"><code class="xref docutils literal notranslate">digitpart</code></a> | <a class="reference internal" href="#grammar-token-float-digitpart"><code class="xref docutils literal notranslate">digitpart</code></a> ["."] exponent ::= ("e" | "E") [<a class="reference internal" href="#grammar-token-float-sign"><code class="xref docutils literal notranslate">sign</code></a>] <a class="reference internal" href="#grammar-token-float-digitpart"><code class="xref docutils literal notranslate">digitpart</code></a> floatnumber ::= <a class="reference internal" href="#grammar-token-float-number"><code class="xref docutils literal notranslate">number</code></a> [<a class="reference internal" href="#grammar-token-float-exponent"><code class="xref docutils literal notranslate">exponent</code></a>] absfloatvalue ::= <a class="reference internal" href="#grammar-token-float-floatnumber"><code class="xref docutils literal notranslate">floatnumber</code></a> | <a class="reference internal" href="#grammar-token-float-infinity"><code class="xref docutils literal notranslate">infinity</code></a> | <a class="reference internal" href="#grammar-token-float-nan"><code class="xref docutils literal notranslate">nan</code></a> floatvalue ::= [<a class="reference internal" href="#grammar-token-float-sign"><code class="xref docutils literal notranslate">sign</code></a>] <a class="reference internal" href="#grammar-token-float-absfloatvalue"><code class="xref docutils literal notranslate">absfloatvalue</code></a> </pre> Case is not significant, so, for example, “inf”, “Inf”, “INFINITY”, and “iNfINity” are all acceptable spellings for positive infinity. Otherwise, if the argument is an integer or a floating-point number, a floating-point number with the same value (within Python’s floating-point precision) is returned. If the argument is outside the range of a Python float, an <a class="reference internal" href="exceptions.html#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal notranslate">OverflowError</code></a> will be raised. For a general Python object <code class="docutils literal notranslate">x</code>, <code class="docutils literal notranslate">float(x)</code> delegates to <code class="docutils literal notranslate">x.__float__()</code>. If <a class="reference internal" href="../reference/datamodel.html#object.__float__" title="object.__float__"><code class="xref py py-meth docutils literal notranslate">__float__()</code></a> is not defined then it falls back to <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">__index__()</code></a>. If no argument is given, <code class="docutils literal notranslate">0.0</code> is returned. The float type is described in <a class="reference internal" href="stdtypes.html#typesnumeric">Numeric Types — int, float, complex</a>. <div class="versionchanged"> Changed in version 3.6: Grouping digits with underscores as in code literals is allowed. </div> <div class="versionchanged"> Changed in version 3.7: The parameter is now positional-only. </div> <div class="versionchanged"> Changed in version 3.8: Falls back to <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">__index__()</code></a> if <a class="reference internal" href="../reference/datamodel.html#object.__float__" title="object.__float__"><code class="xref py py-meth docutils literal notranslate">__float__()</code></a> is not defined. </div> </dd></dl> <dl class="py function" id="index-4"> <dt class="sig sig-object py" id="format"> format(value, format_spec='')<a class="headerlink" href="#format" title="Link to this definition">¶</a></dt> <dd>Convert a value to a “formatted” representation, as controlled by format_spec. The interpretation of format_spec will depend on the type of the value argument; however, there is a standard formatting syntax that is used by most built-in types: <a class="reference internal" href="string.html#formatspec">Format Specification Mini-Language</a>. The default format_spec is an empty string which usually gives the same effect as calling <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-func docutils literal notranslate">str(value)</code></a>. A call to <code class="docutils literal notranslate">format(value, format_spec)</code> is translated to <code class="docutils literal notranslate">type(value).__format__(value, format_spec)</code> which bypasses the instance dictionary when searching for the value’s <a class="reference internal" href="../reference/datamodel.html#object.__format__" title="object.__format__"><code class="xref py py-meth docutils literal notranslate">__format__()</code></a> method. A <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> exception is raised if the method search reaches <a class="reference internal" href="#object" title="object"><code class="xref py py-mod docutils literal notranslate">object</code></a> and the format_spec is non-empty, or if either the format_spec or the return value are not strings. <div class="versionchanged"> Changed in version 3.4: <code class="docutils literal notranslate">object().__format__(format_spec)</code> raises <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> if format_spec is not an empty string. </div> </dd></dl> <dl class="py class" id="func-frozenset"> <dt class="sig sig-object py"> class frozenset(iterable=set())</dt> <dd>Return a new <a class="reference internal" href="stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate">frozenset</code></a> object, optionally with elements taken from iterable. <code class="docutils literal notranslate">frozenset</code> is a built-in class. See <a class="reference internal" href="stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate">frozenset</code></a> and <a class="reference internal" href="stdtypes.html#types-set">Set Types — set, frozenset</a> for documentation about this class. For other containers see the built-in <a class="reference internal" href="stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate">set</code></a>, <a class="reference internal" href="stdtypes.html#list" title="list"><code class="xref py py-class docutils literal notranslate">list</code></a>, <a class="reference internal" href="stdtypes.html#tuple" title="tuple"><code class="xref py py-class docutils literal notranslate">tuple</code></a>, and <a class="reference internal" href="stdtypes.html#dict" title="dict"><code class="xref py py-class docutils literal notranslate">dict</code></a> classes, as well as the <a class="reference internal" href="collections.html#module-collections" title="collections: Container datatypes"><code class="xref py py-mod docutils literal notranslate">collections</code></a> module. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="getattr"> getattr(object, name)<a class="headerlink" href="#getattr" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> getattr(object, name, default)</dt> <dd>Return the value of the named attribute of object. name must be a string. If the string is the name of one of the object’s attributes, the result is the value of that attribute. For example, <code class="docutils literal notranslate">getattr(x, 'foobar')</code> is equivalent to <code class="docutils literal notranslate">x.foobar</code>. If the named attribute does not exist, default is returned if provided, otherwise <a class="reference internal" href="exceptions.html#AttributeError" title="AttributeError"><code class="xref py py-exc docutils literal notranslate">AttributeError</code></a> is raised. name need not be a Python identifier (see <a class="reference internal" href="#setattr" title="setattr"><code class="xref py py-func docutils literal notranslate">setattr()</code></a>). <div class="admonition note"> Note Since <a class="reference internal" href="../reference/expressions.html#private-name-mangling">private name mangling</a> happens at compilation time, one must manually mangle a private attribute’s (attributes with two leading underscores) name in order to retrieve it with <a class="reference internal" href="#getattr" title="getattr"><code class="xref py py-func docutils literal notranslate">getattr()</code></a>. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="globals"> globals()<a class="headerlink" href="#globals" title="Link to this definition">¶</a></dt> <dd>Return the dictionary implementing the current module namespace. For code within functions, this is set when the function is defined and remains the same regardless of where the function is called. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="hasattr"> hasattr(object, name)<a class="headerlink" href="#hasattr" title="Link to this definition">¶</a></dt> <dd>The arguments are an object and a string. The result is <code class="docutils literal notranslate">True</code> if the string is the name of one of the object’s attributes, <code class="docutils literal notranslate">False</code> if not. (This is implemented by calling <code class="docutils literal notranslate">getattr(object, name)</code> and seeing whether it raises an <a class="reference internal" href="exceptions.html#AttributeError" title="AttributeError"><code class="xref py py-exc docutils literal notranslate">AttributeError</code></a> or not.) </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="hash"> hash(object)<a class="headerlink" href="#hash" title="Link to this definition">¶</a></dt> <dd>Return the hash value of the object (if it has one). Hash values are integers. They are used to quickly compare dictionary keys during a dictionary lookup. Numeric values that compare equal have the same hash value (even if they are of different types, as is the case for 1 and 1.0). <div class="admonition note"> Note For objects with custom <a class="reference internal" href="../reference/datamodel.html#object.__hash__" title="object.__hash__"><code class="xref py py-meth docutils literal notranslate">__hash__()</code></a> methods, note that <a class="reference internal" href="#hash" title="hash"><code class="xref py py-func docutils literal notranslate">hash()</code></a> truncates the return value based on the bit width of the host machine. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="help"> help()<a class="headerlink" href="#help" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> help(request)</dt> <dd>Invoke the built-in help system. (This function is intended for interactive use.) If no argument is given, the interactive help system starts on the interpreter console. If the argument is a string, then the string is looked up as the name of a module, function, class, method, keyword, or documentation topic, and a help page is printed on the console. If the argument is any other kind of object, a help page on the object is generated. Note that if a slash(/) appears in the parameter list of a function when invoking <a class="reference internal" href="#help" title="help"><code class="xref py py-func docutils literal notranslate">help()</code></a>, it means that the parameters prior to the slash are positional-only. For more info, see <a class="reference internal" href="../faq/programming.html#faq-positional-only-arguments">the FAQ entry on positional-only parameters</a>. This function is added to the built-in namespace by the <a class="reference internal" href="site.html#module-site" title="site: Module responsible for site-specific configuration."><code class="xref py py-mod docutils literal notranslate">site</code></a> module. <div class="versionchanged"> Changed in version 3.4: Changes to <a class="reference internal" href="pydoc.html#module-pydoc" title="pydoc: Documentation generator and online help system."><code class="xref py py-mod docutils literal notranslate">pydoc</code></a> and <a class="reference internal" href="inspect.html#module-inspect" title="inspect: Extract information and source code from live objects."><code class="xref py py-mod docutils literal notranslate">inspect</code></a> mean that the reported signatures for callables are now more comprehensive and consistent. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="hex"> hex(x)<a class="headerlink" href="#hex" title="Link to this definition">¶</a></dt> <dd>Convert an integer number to a lowercase hexadecimal string prefixed with “0x”. If x is not a Python <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> object, it has to define an <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">__index__()</code></a> method that returns an integer. Some examples: <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> hex(255) '0xff' >>> hex(-42) '-0x2a' </pre></div> </div> If you want to convert an integer number to an uppercase or lower hexadecimal string with prefix or not, you can use either of the following ways: <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> '%#x' % 255, '%x' % 255, '%X' % 255 ('0xff', 'ff', 'FF') >>> format(255, '#x'), format(255, 'x'), format(255, 'X') ('0xff', 'ff', 'FF') >>> f'{255:#x}', f'{255:x}', f'{255:X}' ('0xff', 'ff', 'FF') </pre></div> </div> See also <a class="reference internal" href="#format" title="format"><code class="xref py py-func docutils literal notranslate">format()</code></a> for more information. See also <a class="reference internal" href="#int" title="int"><code class="xref py py-func docutils literal notranslate">int()</code></a> for converting a hexadecimal string to an integer using a base of 16. <div class="admonition note"> Note To obtain a hexadecimal string representation for a float, use the <a class="reference internal" href="stdtypes.html#float.hex" title="float.hex"><code class="xref py py-meth docutils literal notranslate">float.hex()</code></a> method. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="id"> id(object)<a class="headerlink" href="#id" title="Link to this definition">¶</a></dt> <dd>Return the “identity” of an object. This is an integer which is guaranteed to be unique and constant for this object during its lifetime. Two objects with non-overlapping lifetimes may have the same <a class="reference internal" href="#id" title="id"><code class="xref py py-func docutils literal notranslate">id()</code></a> value. <div class="impl-detail compound"> CPython implementation detail: This is the address of the object in memory. </div> Raises an <a class="reference internal" href="sys.html#auditing">auditing event</a> <code class="docutils literal notranslate">builtins.id</code> with argument <code class="docutils literal notranslate">id</code>. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="input"> input()<a class="headerlink" href="#input" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> input(prompt)</dt> <dd>If the prompt argument is present, it is written to standard output without a trailing newline. The function then reads a line from input, converts it to a string (stripping a trailing newline), and returns that. When EOF is read, <a class="reference internal" href="exceptions.html#EOFError" title="EOFError"><code class="xref py py-exc docutils literal notranslate">EOFError</code></a> is raised. Example: <div class="highlight-python3 notranslate"><div class="highlight"><pre>>>> s = input('--> ') --> Monty Python's Flying Circus >>> s "Monty Python's Flying Circus" </pre></div> </div> If the <a class="reference internal" href="readline.html#module-readline" title="readline: GNU readline support for Python. (Unix)"><code class="xref py py-mod docutils literal notranslate">readline</code></a> module was loaded, then <a class="reference internal" href="#input" title="input"><code class="xref py py-func docutils literal notranslate">input()</code></a> will use it to provide elaborate line editing and history features. Raises an <a class="reference internal" href="sys.html#auditing">auditing event</a> <code class="docutils literal notranslate">builtins.input</code> with argument <code class="docutils literal notranslate">prompt</code> before reading input Raises an <a class="reference internal" href="sys.html#auditing">auditing event</a> <code class="docutils literal notranslate">builtins.input/result</code> with the result after successfully reading input. </dd></dl> <dl class="py class"> <dt class="sig sig-object py" id="int"> class int(number=0, /)<a class="headerlink" href="#int" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> class int(string, /, base=10)</dt> <dd>Return an integer object constructed from a number or a string, or return <code class="docutils literal notranslate">0</code> if no arguments are given. Examples: <div class="highlight-pycon notranslate"><div class="highlight"><pre>>>> int(123.45) 123 >>> int('123') 123 >>> int(' -12_345\n') -12345 >>> int('FACE', 16) 64206 >>> int('0xface', 0) 64206 >>> int('01110011', base=2) 115 </pre></div> </div> If the argument defines <a class="reference internal" href="../reference/datamodel.html#object.__int__" title="object.__int__"><code class="xref py py-meth docutils literal notranslate">__int__()</code></a>, <code class="docutils literal notranslate">int(x)</code> returns <code class="docutils literal notranslate">x.__int__()</code>. If the argument defines <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">__index__()</code></a>, it returns <code class="docutils literal notranslate">x.__index__()</code>. If the argument defines <a class="reference internal" href="../reference/datamodel.html#object.__trunc__" title="object.__trunc__"><code class="xref py py-meth docutils literal notranslate">__trunc__()</code></a>, it returns <code class="docutils literal notranslate">x.__trunc__()</code>. For floating-point numbers, this truncates towards zero. If the argument is not a number or if base is given, then it must be a string, <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate">bytes</code></a>, or <a class="reference internal" href="stdtypes.html#bytearray" title="bytearray"><code class="xref py py-class docutils literal notranslate">bytearray</code></a> instance representing an integer in radix base. Optionally, the string can be preceded by <code class="docutils literal notranslate">+</code> or <code class="docutils literal notranslate">-</code> (with no space in between), have leading zeros, be surrounded by whitespace, and have single underscores interspersed between digits. A base-n integer string contains digits, each representing a value from 0 to n-1. The values 0–9 can be represented by any Unicode decimal digit. The values 10–35 can be represented by <code class="docutils literal notranslate">a</code> to <code class="docutils literal notranslate">z</code> (or <code class="docutils literal notranslate">A</code> to <code class="docutils literal notranslate">Z</code>). The default base is 10. The allowed bases are 0 and 2–36. Base-2, -8, and -16 strings can be optionally prefixed with <code class="docutils literal notranslate">0b</code>/<code class="docutils literal notranslate">0B</code>, <code class="docutils literal notranslate">0o</code>/<code class="docutils literal notranslate">0O</code>, or <code class="docutils literal notranslate">0x</code>/<code class="docutils literal notranslate">0X</code>, as with integer literals in code. For base 0, the string is interpreted in a similar way to an <a class="reference internal" href="../reference/lexical_analysis.html#integers">integer literal in code</a>, in that the actual base is 2, 8, 10, or 16 as determined by the prefix. Base 0 also disallows leading zeros: <code class="docutils literal notranslate">int('010', 0)</code> is not legal, while <code class="docutils literal notranslate">int('010')</code> and <code class="docutils literal notranslate">int('010', 8)</code> are. The integer type is described in <a class="reference internal" href="stdtypes.html#typesnumeric">Numeric Types — int, float, complex</a>. <div class="versionchanged"> Changed in version 3.4: If base is not an instance of <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> and the base object has a <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">base.__index__</code></a> method, that method is called to obtain an integer for the base. Previous versions used <a class="reference internal" href="../reference/datamodel.html#object.__int__" title="object.__int__"><code class="xref py py-meth docutils literal notranslate">base.__int__</code></a> instead of <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">base.__index__</code></a>. </div> <div class="versionchanged"> Changed in version 3.6: Grouping digits with underscores as in code literals is allowed. </div> <div class="versionchanged"> Changed in version 3.7: The first parameter is now positional-only. </div> <div class="versionchanged"> Changed in version 3.8: Falls back to <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">__index__()</code></a> if <a class="reference internal" href="../reference/datamodel.html#object.__int__" title="object.__int__"><code class="xref py py-meth docutils literal notranslate">__int__()</code></a> is not defined. </div> <div class="versionchanged"> Changed in version 3.11: The delegation to <a class="reference internal" href="../reference/datamodel.html#object.__trunc__" title="object.__trunc__"><code class="xref py py-meth docutils literal notranslate">__trunc__()</code></a> is deprecated. </div> <div class="versionchanged"> Changed in version 3.11: <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> string inputs and string representations can be limited to help avoid denial of service attacks. A <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate">ValueError</code></a> is raised when the limit is exceeded while converting a string to an <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> or when converting an <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> into a string would exceed the limit. See the <a class="reference internal" href="stdtypes.html#int-max-str-digits">integer string conversion length limitation</a> documentation. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="isinstance"> isinstance(object, classinfo)<a class="headerlink" href="#isinstance" title="Link to this definition">¶</a></dt> <dd>Return <code class="docutils literal notranslate">True</code> if the object argument is an instance of the classinfo argument, or of a (direct, indirect, or <a class="reference internal" href="../glossary.html#term-abstract-base-class">virtual</a>) subclass thereof. If object is not an object of the given type, the function always returns <code class="docutils literal notranslate">False</code>. If classinfo is a tuple of type objects (or recursively, other such tuples) or a <a class="reference internal" href="stdtypes.html#types-union">Union Type</a> of multiple types, return <code class="docutils literal notranslate">True</code> if object is an instance of any of the types. If classinfo is not a type or tuple of types and such tuples, a <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> exception is raised. <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> may not be raised for an invalid type if an earlier check succeeds. <div class="versionchanged"> Changed in version 3.10: classinfo can be a <a class="reference internal" href="stdtypes.html#types-union">Union Type</a>. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="issubclass"> issubclass(class, classinfo)<a class="headerlink" href="#issubclass" title="Link to this definition">¶</a></dt> <dd>Return <code class="docutils literal notranslate">True</code> if class is a subclass (direct, indirect, or <a class="reference internal" href="../glossary.html#term-abstract-base-class">virtual</a>) of classinfo. A class is considered a subclass of itself. classinfo may be a tuple of class objects (or recursively, other such tuples) or a <a class="reference internal" href="stdtypes.html#types-union">Union Type</a>, in which case return <code class="docutils literal notranslate">True</code> if class is a subclass of any entry in classinfo. In any other case, a <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> exception is raised. <div class="versionchanged"> Changed in version 3.10: classinfo can be a <a class="reference internal" href="stdtypes.html#types-union">Union Type</a>. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="iter"> iter(object)<a class="headerlink" href="#iter" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> iter(object, sentinel)</dt> <dd>Return an <a class="reference internal" href="../glossary.html#term-iterator">iterator</a> object. The first argument is interpreted very differently depending on the presence of the second argument. Without a second argument, object must be a collection object which supports the <a class="reference internal" href="../glossary.html#term-iterable">iterable</a> protocol (the <a class="reference internal" href="../reference/datamodel.html#object.__iter__" title="object.__iter__"><code class="xref py py-meth docutils literal notranslate">__iter__()</code></a> method), or it must support the sequence protocol (the <a class="reference internal" href="../reference/datamodel.html#object.__getitem__" title="object.__getitem__"><code class="xref py py-meth docutils literal notranslate">__getitem__()</code></a> method with integer arguments starting at <code class="docutils literal notranslate">0</code>). If it does not support either of those protocols, <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> is raised. If the second argument, sentinel, is given, then object must be a callable object. The iterator created in this case will call object with no arguments for each call to its <a class="reference internal" href="stdtypes.html#iterator.__next__" title="iterator.__next__"><code class="xref py py-meth docutils literal notranslate">__next__()</code></a> method; if the value returned is equal to sentinel, <a class="reference internal" href="exceptions.html#StopIteration" title="StopIteration"><code class="xref py py-exc docutils literal notranslate">StopIteration</code></a> will be raised, otherwise the value will be returned. See also <a class="reference internal" href="stdtypes.html#typeiter">Iterator Types</a>. One useful application of the second form of <a class="reference internal" href="#iter" title="iter"><code class="xref py py-func docutils literal notranslate">iter()</code></a> is to build a block-reader. For example, reading fixed-width blocks from a binary database file until the end of file is reached: <div class="highlight-python3 notranslate"><div class="highlight"><pre>from functools import partial with open('mydata.db', 'rb') as f: for block in iter(partial(f.read, 64), b''): process_block(block) </pre></div> </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="len"> len(s)<a class="headerlink" href="#len" title="Link to this definition">¶</a></dt> <dd>Return the length (the number of items) of an object. The argument may be a sequence (such as a string, bytes, tuple, list, or range) or a collection (such as a dictionary, set, or frozen set). <div class="impl-detail compound"> CPython implementation detail: <code class="docutils literal notranslate">len</code> raises <a class="reference internal" href="exceptions.html#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal notranslate">OverflowError</code></a> on lengths larger than <a class="reference internal" href="sys.html#sys.maxsize" title="sys.maxsize"><code class="xref py py-data docutils literal notranslate">sys.maxsize</code></a>, such as <a class="reference internal" href="stdtypes.html#range" title="range"><code class="xref py py-class docutils literal notranslate">range(2 ** 100)</code></a>. </div> </dd></dl> <dl class="py class" id="func-list"> <dt class="sig sig-object py"> class list</dt> <dt class="sig sig-object py"> class list(iterable)</dt> <dd>Rather than being a function, <a class="reference internal" href="stdtypes.html#list" title="list"><code class="xref py py-class docutils literal notranslate">list</code></a> is actually a mutable sequence type, as documented in <a class="reference internal" href="stdtypes.html#typesseq-list">Lists</a> and <a class="reference internal" href="stdtypes.html#typesseq">Sequence Types — list, tuple, range</a>. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="locals"> locals()<a class="headerlink" href="#locals" title="Link to this definition">¶</a></dt> <dd><blockquote> <div>Return a mapping object representing the current local symbol table, with variable names as the keys, and their currently bound references as the values. At module scope, as well as when using <a class="reference internal" href="#exec" title="exec"><code class="xref py py-func docutils literal notranslate">exec()</code></a> or <a class="reference internal" href="#eval" title="eval"><code class="xref py py-func docutils literal notranslate">eval()</code></a> with a single namespace, this function returns the same namespace as <a class="reference internal" href="#globals" title="globals"><code class="xref py py-func docutils literal notranslate">globals()</code></a>. At class scope, it returns the namespace that will be passed to the metaclass constructor. When using <code class="docutils literal notranslate">exec()</code> or <code class="docutils literal notranslate">eval()</code> with separate local and global arguments, it returns the local namespace passed in to the function call. In all of the above cases, each call to <code class="docutils literal notranslate">locals()</code> in a given frame of execution will return the same mapping object. Changes made through the mapping object returned from <code class="docutils literal notranslate">locals()</code> will be visible as assigned, reassigned, or deleted local variables, and assigning, reassigning, or deleting local variables will immediately affect the contents of the returned mapping object. In an <a class="reference internal" href="../glossary.html#term-optimized-scope">optimized scope</a> (including functions, generators, and coroutines), each call to <code class="docutils literal notranslate">locals()</code> instead returns a fresh dictionary containing the current bindings of the function’s local variables and any nonlocal cell references. In this case, name binding changes made via the returned dict are not written back to the corresponding local variables or nonlocal cell references, and assigning, reassigning, or deleting local variables and nonlocal cell references does not affect the contents of previously returned dictionaries. Calling <code class="docutils literal notranslate">locals()</code> as part of a comprehension in a function, generator, or coroutine is equivalent to calling it in the containing scope, except that the comprehension’s initialised iteration variables will be included. In other scopes, it behaves as if the comprehension were running as a nested function. Calling <code class="docutils literal notranslate">locals()</code> as part of a generator expression is equivalent to calling it in a nested generator function. </div></blockquote> <div class="versionchanged"> Changed in version 3.12: The behaviour of <code class="docutils literal notranslate">locals()</code> in a comprehension has been updated as described in <a class="pep reference external" href="https://peps.python.org/pep-0709/">PEP 709</a>. </div> <div class="versionchanged"> Changed in version 3.13: As part of <a class="pep reference external" href="https://peps.python.org/pep-0667/">PEP 667</a>, the semantics of mutating the mapping objects returned from this function are now defined. The behavior in <a class="reference internal" href="../glossary.html#term-optimized-scope">optimized scopes</a> is now as described above. Aside from being defined, the behaviour in other scopes remains unchanged from previous versions. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="map"> map(function, iterable, *iterables)<a class="headerlink" href="#map" title="Link to this definition">¶</a></dt> <dd>Return an iterator that applies function to every item of iterable, yielding the results. If additional iterables arguments are passed, function must take that many arguments and is applied to the items from all iterables in parallel. With multiple iterables, the iterator stops when the shortest iterable is exhausted. For cases where the function inputs are already arranged into argument tuples, see <a class="reference internal" href="itertools.html#itertools.starmap" title="itertools.starmap"><code class="xref py py-func docutils literal notranslate">itertools.starmap()</code></a>. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="max"> max(iterable, *, key=None)<a class="headerlink" href="#max" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> max(iterable, *, default, key=None)</dt> <dt class="sig sig-object py"> max(arg1, arg2, *args, key=None)</dt> <dd>Return the largest item in an iterable or the largest of two or more arguments. If one positional argument is provided, it should be an <a class="reference internal" href="../glossary.html#term-iterable">iterable</a>. The largest item in the iterable is returned. If two or more positional arguments are provided, the largest of the positional arguments is returned. There are two optional keyword-only arguments. The key argument specifies a one-argument ordering function like that used for <a class="reference internal" href="stdtypes.html#list.sort" title="list.sort"><code class="xref py py-meth docutils literal notranslate">list.sort()</code></a>. The default argument specifies an object to return if the provided iterable is empty. If the iterable is empty and default is not provided, a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate">ValueError</code></a> is raised. If multiple items are maximal, the function returns the first one encountered. This is consistent with other sort-stability preserving tools such as <code class="docutils literal notranslate">sorted(iterable, key=keyfunc, reverse=True)[0]</code> and <code class="docutils literal notranslate">heapq.nlargest(1, iterable, key=keyfunc)</code>. <div class="versionchanged"> Changed in version 3.4: Added the default keyword-only parameter. </div> <div class="versionchanged"> Changed in version 3.8: The key can be <code class="docutils literal notranslate">None</code>. </div> </dd></dl> <dl class="py class" id="func-memoryview"> <dt class="sig sig-object py"> class memoryview(object)</dt> <dd>Return a “memory view” object created from the given argument. See <a class="reference internal" href="stdtypes.html#typememoryview">Memory Views</a> for more information. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="min"> min(iterable, *, key=None)<a class="headerlink" href="#min" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> min(iterable, *, default, key=None)</dt> <dt class="sig sig-object py"> min(arg1, arg2, *args, key=None)</dt> <dd>Return the smallest item in an iterable or the smallest of two or more arguments. If one positional argument is provided, it should be an <a class="reference internal" href="../glossary.html#term-iterable">iterable</a>. The smallest item in the iterable is returned. If two or more positional arguments are provided, the smallest of the positional arguments is returned. There are two optional keyword-only arguments. The key argument specifies a one-argument ordering function like that used for <a class="reference internal" href="stdtypes.html#list.sort" title="list.sort"><code class="xref py py-meth docutils literal notranslate">list.sort()</code></a>. The default argument specifies an object to return if the provided iterable is empty. If the iterable is empty and default is not provided, a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate">ValueError</code></a> is raised. If multiple items are minimal, the function returns the first one encountered. This is consistent with other sort-stability preserving tools such as <code class="docutils literal notranslate">sorted(iterable, key=keyfunc)[0]</code> and <code class="docutils literal notranslate">heapq.nsmallest(1, iterable, key=keyfunc)</code>. <div class="versionchanged"> Changed in version 3.4: Added the default keyword-only parameter. </div> <div class="versionchanged"> Changed in version 3.8: The key can be <code class="docutils literal notranslate">None</code>. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="next"> next(iterator)<a class="headerlink" href="#next" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> next(iterator, default)</dt> <dd>Retrieve the next item from the <a class="reference internal" href="../glossary.html#term-iterator">iterator</a> by calling its <a class="reference internal" href="stdtypes.html#iterator.__next__" title="iterator.__next__"><code class="xref py py-meth docutils literal notranslate">__next__()</code></a> method. If default is given, it is returned if the iterator is exhausted, otherwise <a class="reference internal" href="exceptions.html#StopIteration" title="StopIteration"><code class="xref py py-exc docutils literal notranslate">StopIteration</code></a> is raised. </dd></dl> <dl class="py class"> <dt class="sig sig-object py" id="object"> class object<a class="headerlink" href="#object" title="Link to this definition">¶</a></dt> <dd>This is the ultimate base class of all other classes. It has methods that are common to all instances of Python classes. When the constructor is called, it returns a new featureless object. The constructor does not accept any arguments. <div class="admonition note"> Note <a class="reference internal" href="#object" title="object"><code class="xref py py-class docutils literal notranslate">object</code></a> instances do not have <a class="reference internal" href="../reference/datamodel.html#object.__dict__" title="object.__dict__"><code class="xref py py-attr docutils literal notranslate">__dict__</code></a> attributes, so you can’t assign arbitrary attributes to an instance of <a class="reference internal" href="#object" title="object"><code class="xref py py-class docutils literal notranslate">object</code></a>. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="oct"> oct(x)<a class="headerlink" href="#oct" title="Link to this definition">¶</a></dt> <dd>Convert an integer number to an octal string prefixed with “0o”. The result is a valid Python expression. If x is not a Python <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> object, it has to define an <a class="reference internal" href="../reference/datamodel.html#object.__index__" title="object.__index__"><code class="xref py py-meth docutils literal notranslate">__index__()</code></a> method that returns an integer. For example: <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> oct(8) '0o10' >>> oct(-56) '-0o70' </pre></div> </div> If you want to convert an integer number to an octal string either with the prefix “0o” or not, you can use either of the following ways. <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> '%#o' % 10, '%o' % 10 ('0o12', '12') >>> format(10, '#o'), format(10, 'o') ('0o12', '12') >>> f'{10:#o}', f'{10:o}' ('0o12', '12') </pre></div> </div> See also <a class="reference internal" href="#format" title="format"><code class="xref py py-func docutils literal notranslate">format()</code></a> for more information. </dd></dl> <dl class="py function" id="index-7"> <dt class="sig sig-object py" id="open"> open(file, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)<a class="headerlink" href="#open" title="Link to this definition">¶</a></dt> <dd>Open file and return a corresponding <a class="reference internal" href="../glossary.html#term-file-object">file object</a>. If the file cannot be opened, an <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate">OSError</code></a> is raised. See <a class="reference internal" href="../tutorial/inputoutput.html#tut-files">Reading and Writing Files</a> for more examples of how to use this function. file is a <a class="reference internal" href="../glossary.html#term-path-like-object">path-like object</a> giving the pathname (absolute or relative to the current working directory) of the file to be opened or an integer file descriptor of the file to be wrapped. (If a file descriptor is given, it is closed when the returned I/O object is closed unless closefd is set to <code class="docutils literal notranslate">False</code>.) mode is an optional string that specifies the mode in which the file is opened. It defaults to <code class="docutils literal notranslate">'r'</code> which means open for reading in text mode. Other common values are <code class="docutils literal notranslate">'w'</code> for writing (truncating the file if it already exists), <code class="docutils literal notranslate">'x'</code> for exclusive creation, and <code class="docutils literal notranslate">'a'</code> for appending (which on some Unix systems, means that all writes append to the end of the file regardless of the current seek position). In text mode, if encoding is not specified the encoding used is platform-dependent: <a class="reference internal" href="locale.html#locale.getencoding" title="locale.getencoding"><code class="xref py py-func docutils literal notranslate">locale.getencoding()</code></a> is called to get the current locale encoding. (For reading and writing raw bytes use binary mode and leave encoding unspecified.) The available modes are: <table class="docutils align-default" id="index-8"> <thead> <tr class="row-odd"><th class="head">Character</th> <th class="head">Meaning</th> </tr> </thead> <tbody> <tr class="row-even"><td><code class="docutils literal notranslate">'r'</code></td> <td>open for reading (default)</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate">'w'</code></td> <td>open for writing, truncating the file first</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate">'x'</code></td> <td>open for exclusive creation, failing if the file already exists</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate">'a'</code></td> <td>open for writing, appending to the end of file if it exists</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate">'b'</code></td> <td>binary mode</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate">'t'</code></td> <td>text mode (default)</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate">'+'</code></td> <td>open for updating (reading and writing)</td> </tr> </tbody> </table> The default mode is <code class="docutils literal notranslate">'r'</code> (open for reading text, a synonym of <code class="docutils literal notranslate">'rt'</code>). Modes <code class="docutils literal notranslate">'w+'</code> and <code class="docutils literal notranslate">'w+b'</code> open and truncate the file. Modes <code class="docutils literal notranslate">'r+'</code> and <code class="docutils literal notranslate">'r+b'</code> open the file with no truncation. As mentioned in the <a class="reference internal" href="io.html#io-overview">Overview</a>, Python distinguishes between binary and text I/O. Files opened in binary mode (including <code class="docutils literal notranslate">'b'</code> in the mode argument) return contents as <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate">bytes</code></a> objects without any decoding. In text mode (the default, or when <code class="docutils literal notranslate">'t'</code> is included in the mode argument), the contents of the file are returned as <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-class docutils literal notranslate">str</code></a>, the bytes having been first decoded using a platform-dependent encoding or using the specified encoding if given. <div class="admonition note"> Note Python doesn’t depend on the underlying operating system’s notion of text files; all the processing is done by Python itself, and is therefore platform-independent. </div> buffering is an optional integer used to set the buffering policy. Pass 0 to switch buffering off (only allowed in binary mode), 1 to select line buffering (only usable when writing in text mode), and an integer > 1 to indicate the size in bytes of a fixed-size chunk buffer. Note that specifying a buffer size this way applies for binary buffered I/O, but <code class="docutils literal notranslate">TextIOWrapper</code> (i.e., files opened with <code class="docutils literal notranslate">mode='r+'</code>) would have another buffering. To disable buffering in <code class="docutils literal notranslate">TextIOWrapper</code>, consider using the <code class="docutils literal notranslate">write_through</code> flag for <a class="reference internal" href="io.html#io.TextIOWrapper.reconfigure" title="io.TextIOWrapper.reconfigure"><code class="xref py py-func docutils literal notranslate">io.TextIOWrapper.reconfigure()</code></a>. When no buffering argument is given, the default buffering policy works as follows: <ul class="simple"> <li>Binary files are buffered in fixed-size chunks; the size of the buffer is chosen using a heuristic trying to determine the underlying device’s “block size” and falling back on <a class="reference internal" href="io.html#io.DEFAULT_BUFFER_SIZE" title="io.DEFAULT_BUFFER_SIZE"><code class="xref py py-const docutils literal notranslate">io.DEFAULT_BUFFER_SIZE</code></a>. On many systems, the buffer will typically be 4096 or 8192 bytes long.</li> <li>“Interactive” text files (files for which <a class="reference internal" href="io.html#io.IOBase.isatty" title="io.IOBase.isatty"><code class="xref py py-meth docutils literal notranslate">isatty()</code></a> returns <code class="docutils literal notranslate">True</code>) use line buffering. Other text files use the policy described above for binary files.</li> </ul> encoding is the name of the encoding used to decode or encode the file. This should only be used in text mode. The default encoding is platform dependent (whatever <a class="reference internal" href="locale.html#locale.getencoding" title="locale.getencoding"><code class="xref py py-func docutils literal notranslate">locale.getencoding()</code></a> returns), but any <a class="reference internal" href="../glossary.html#term-text-encoding">text encoding</a> supported by Python can be used. See the <a class="reference internal" href="codecs.html#module-codecs" title="codecs: Encode and decode data and streams."><code class="xref py py-mod docutils literal notranslate">codecs</code></a> module for the list of supported encodings. errors is an optional string that specifies how encoding and decoding errors are to be handled—this cannot be used in binary mode. A variety of standard error handlers are available (listed under <a class="reference internal" href="codecs.html#error-handlers">Error Handlers</a>), though any error handling name that has been registered with <a class="reference internal" href="codecs.html#codecs.register_error" title="codecs.register_error"><code class="xref py py-func docutils literal notranslate">codecs.register_error()</code></a> is also valid. The standard names include: <ul class="simple"> <li><code class="docutils literal notranslate">'strict'</code> to raise a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate">ValueError</code></a> exception if there is an encoding error. The default value of <code class="docutils literal notranslate">None</code> has the same effect.</li> <li><code class="docutils literal notranslate">'ignore'</code> ignores errors. Note that ignoring encoding errors can lead to data loss.</li> <li><code class="docutils literal notranslate">'replace'</code> causes a replacement marker (such as <code class="docutils literal notranslate">'?'</code>) to be inserted where there is malformed data.</li> <li><code class="docutils literal notranslate">'surrogateescape'</code> will represent any incorrect bytes as low surrogate code units ranging from U+DC80 to U+DCFF. These surrogate code units will then be turned back into the same bytes when the <code class="docutils literal notranslate">surrogateescape</code> error handler is used when writing data. This is useful for processing files in an unknown encoding.</li> <li><code class="docutils literal notranslate">'xmlcharrefreplace'</code> is only supported when writing to a file. Characters not supported by the encoding are replaced with the appropriate XML character reference <code class="samp docutils literal notranslate">&#nnn;</code>.</li> <li><code class="docutils literal notranslate">'backslashreplace'</code> replaces malformed data by Python’s backslashed escape sequences.</li> <li><code class="docutils literal notranslate">'namereplace'</code> (also only supported when writing) replaces unsupported characters with <code class="docutils literal notranslate">\N{...}</code> escape sequences.</li> </ul> newline determines how to parse newline characters from the stream. It can be <code class="docutils literal notranslate">None</code>, <code class="docutils literal notranslate">''</code>, <code class="docutils literal notranslate">'\n'</code>, <code class="docutils literal notranslate">'\r'</code>, and <code class="docutils literal notranslate">'\r\n'</code>. It works as follows: <ul class="simple"> <li>When reading input from the stream, if newline is <code class="docutils literal notranslate">None</code>, universal newlines mode is enabled. Lines in the input can end in <code class="docutils literal notranslate">'\n'</code>, <code class="docutils literal notranslate">'\r'</code>, or <code class="docutils literal notranslate">'\r\n'</code>, and these are translated into <code class="docutils literal notranslate">'\n'</code> before being returned to the caller. If it is <code class="docutils literal notranslate">''</code>, universal newlines mode is enabled, but line endings are returned to the caller untranslated. If it has any of the other legal values, input lines are only terminated by the given string, and the line ending is returned to the caller untranslated.</li> <li>When writing output to the stream, if newline is <code class="docutils literal notranslate">None</code>, any <code class="docutils literal notranslate">'\n'</code> characters written are translated to the system default line separator, <a class="reference internal" href="os.html#os.linesep" title="os.linesep"><code class="xref py py-data docutils literal notranslate">os.linesep</code></a>. If newline is <code class="docutils literal notranslate">''</code> or <code class="docutils literal notranslate">'\n'</code>, no translation takes place. If newline is any of the other legal values, any <code class="docutils literal notranslate">'\n'</code> characters written are translated to the given string.</li> </ul> If closefd is <code class="docutils literal notranslate">False</code> and a file descriptor rather than a filename was given, the underlying file descriptor will be kept open when the file is closed. If a filename is given closefd must be <code class="docutils literal notranslate">True</code> (the default); otherwise, an error will be raised. A custom opener can be used by passing a callable as opener. The underlying file descriptor for the file object is then obtained by calling opener with (file, flags). opener must return an open file descriptor (passing <a class="reference internal" href="os.html#os.open" title="os.open"><code class="xref py py-mod docutils literal notranslate">os.open</code></a> as opener results in functionality similar to passing <code class="docutils literal notranslate">None</code>). The newly created file is <a class="reference internal" href="os.html#fd-inheritance">non-inheritable</a>. The following example uses the <a class="reference internal" href="os.html#dir-fd">dir_fd</a> parameter of the <a class="reference internal" href="os.html#os.open" title="os.open"><code class="xref py py-func docutils literal notranslate">os.open()</code></a> function to open a file relative to a given directory: <div class="highlight-python3 notranslate"><div class="highlight"><pre>>>> import os >>> dir_fd = os.open('somedir', os.O_RDONLY) >>> def opener(path, flags): ... return os.open(path, flags, dir_fd=dir_fd) ... >>> with open('spamspam.txt', 'w', opener=opener) as f: ... print('This will be written to somedir/spamspam.txt', file=f) ... >>> os.close(dir_fd) # don't leak a file descriptor </pre></div> </div> The type of <a class="reference internal" href="../glossary.html#term-file-object">file object</a> returned by the <a class="reference internal" href="#open" title="open"><code class="xref py py-func docutils literal notranslate">open()</code></a> function depends on the mode. When <a class="reference internal" href="#open" title="open"><code class="xref py py-func docutils literal notranslate">open()</code></a> is used to open a file in a text mode (<code class="docutils literal notranslate">'w'</code>, <code class="docutils literal notranslate">'r'</code>, <code class="docutils literal notranslate">'wt'</code>, <code class="docutils literal notranslate">'rt'</code>, etc.), it returns a subclass of <a class="reference internal" href="io.html#io.TextIOBase" title="io.TextIOBase"><code class="xref py py-class docutils literal notranslate">io.TextIOBase</code></a> (specifically <a class="reference internal" href="io.html#io.TextIOWrapper" title="io.TextIOWrapper"><code class="xref py py-class docutils literal notranslate">io.TextIOWrapper</code></a>). When used to open a file in a binary mode with buffering, the returned class is a subclass of <a class="reference internal" href="io.html#io.BufferedIOBase" title="io.BufferedIOBase"><code class="xref py py-class docutils literal notranslate">io.BufferedIOBase</code></a>. The exact class varies: in read binary mode, it returns an <a class="reference internal" href="io.html#io.BufferedReader" title="io.BufferedReader"><code class="xref py py-class docutils literal notranslate">io.BufferedReader</code></a>; in write binary and append binary modes, it returns an <a class="reference internal" href="io.html#io.BufferedWriter" title="io.BufferedWriter"><code class="xref py py-class docutils literal notranslate">io.BufferedWriter</code></a>, and in read/write mode, it returns an <a class="reference internal" href="io.html#io.BufferedRandom" title="io.BufferedRandom"><code class="xref py py-class docutils literal notranslate">io.BufferedRandom</code></a>. When buffering is disabled, the raw stream, a subclass of <a class="reference internal" href="io.html#io.RawIOBase" title="io.RawIOBase"><code class="xref py py-class docutils literal notranslate">io.RawIOBase</code></a>, <a class="reference internal" href="io.html#io.FileIO" title="io.FileIO"><code class="xref py py-class docutils literal notranslate">io.FileIO</code></a>, is returned. See also the file handling modules, such as <a class="reference internal" href="fileinput.html#module-fileinput" title="fileinput: Loop over standard input or a list of files."><code class="xref py py-mod docutils literal notranslate">fileinput</code></a>, <a class="reference internal" href="io.html#module-io" title="io: Core tools for working with streams."><code class="xref py py-mod docutils literal notranslate">io</code></a> (where <a class="reference internal" href="#open" title="open"><code class="xref py py-func docutils literal notranslate">open()</code></a> is declared), <a class="reference internal" href="os.html#module-os" title="os: Miscellaneous operating system interfaces."><code class="xref py py-mod docutils literal notranslate">os</code></a>, <a class="reference internal" href="os.path.html#module-os.path" title="os.path: Operations on pathnames."><code class="xref py py-mod docutils literal notranslate">os.path</code></a>, <a class="reference internal" href="tempfile.html#module-tempfile" title="tempfile: Generate temporary files and directories."><code class="xref py py-mod docutils literal notranslate">tempfile</code></a>, and <a class="reference internal" href="shutil.html#module-shutil" title="shutil: High-level file operations, including copying."><code class="xref py py-mod docutils literal notranslate">shutil</code></a>. Raises an <a class="reference internal" href="sys.html#auditing">auditing event</a> <code class="docutils literal notranslate">open</code> with arguments <code class="docutils literal notranslate">path</code>, <code class="docutils literal notranslate">mode</code>, <code class="docutils literal notranslate">flags</code>. The <code class="docutils literal notranslate">mode</code> and <code class="docutils literal notranslate">flags</code> arguments may have been modified or inferred from the original call. <div class="versionchanged"> Changed in version 3.3: <ul class="simple"> <li>The opener parameter was added.</li> <li>The <code class="docutils literal notranslate">'x'</code> mode was added.</li> <li><a class="reference internal" href="exceptions.html#IOError" title="IOError"><code class="xref py py-exc docutils literal notranslate">IOError</code></a> used to be raised, it is now an alias of <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate">OSError</code></a>.</li> <li><a class="reference internal" href="exceptions.html#FileExistsError" title="FileExistsError"><code class="xref py py-exc docutils literal notranslate">FileExistsError</code></a> is now raised if the file opened in exclusive creation mode (<code class="docutils literal notranslate">'x'</code>) already exists.</li> </ul> </div> <div class="versionchanged"> Changed in version 3.4: <ul class="simple"> <li>The file is now non-inheritable.</li> </ul> </div> <div class="versionchanged"> Changed in version 3.5: <ul class="simple"> <li>If the system call is interrupted and the signal handler does not raise an exception, the function now retries the system call instead of raising an <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate">InterruptedError</code></a> exception (see <a class="pep reference external" href="https://peps.python.org/pep-0475/">PEP 475</a> for the rationale).</li> <li>The <code class="docutils literal notranslate">'namereplace'</code> error handler was added.</li> </ul> </div> <div class="versionchanged"> Changed in version 3.6: <ul class="simple"> <li>Support added to accept objects implementing <a class="reference internal" href="os.html#os.PathLike" title="os.PathLike"><code class="xref py py-class docutils literal notranslate">os.PathLike</code></a>.</li> <li>On Windows, opening a console buffer may return a subclass of <a class="reference internal" href="io.html#io.RawIOBase" title="io.RawIOBase"><code class="xref py py-class docutils literal notranslate">io.RawIOBase</code></a> other than <a class="reference internal" href="io.html#io.FileIO" title="io.FileIO"><code class="xref py py-class docutils literal notranslate">io.FileIO</code></a>.</li> </ul> </div> <div class="versionchanged"> Changed in version 3.11: The <code class="docutils literal notranslate">'U'</code> mode has been removed. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="ord"> ord(c)<a class="headerlink" href="#ord" title="Link to this definition">¶</a></dt> <dd>Given a string representing one Unicode character, return an integer representing the Unicode code point of that character. For example, <code class="docutils literal notranslate">ord('a')</code> returns the integer <code class="docutils literal notranslate">97</code> and <code class="docutils literal notranslate">ord('€')</code> (Euro sign) returns <code class="docutils literal notranslate">8364</code>. This is the inverse of <a class="reference internal" href="#chr" title="chr"><code class="xref py py-func docutils literal notranslate">chr()</code></a>. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="pow"> pow(base, exp, mod=None)<a class="headerlink" href="#pow" title="Link to this definition">¶</a></dt> <dd>Return base to the power exp; if mod is present, return base to the power exp, modulo mod (computed more efficiently than <code class="docutils literal notranslate">pow(base, exp) % mod</code>). The two-argument form <code class="docutils literal notranslate">pow(base, exp)</code> is equivalent to using the power operator: <code class="docutils literal notranslate">base**exp</code>. The arguments must have numeric types. With mixed operand types, the coercion rules for binary arithmetic operators apply. For <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> operands, the result has the same type as the operands (after coercion) unless the second argument is negative; in that case, all arguments are converted to float and a float result is delivered. For example, <code class="docutils literal notranslate">pow(10, 2)</code> returns <code class="docutils literal notranslate">100</code>, but <code class="docutils literal notranslate">pow(10, -2)</code> returns <code class="docutils literal notranslate">0.01</code>. For a negative base of type <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> or <a class="reference internal" href="#float" title="float"><code class="xref py py-class docutils literal notranslate">float</code></a> and a non-integral exponent, a complex result is delivered. For example, <code class="docutils literal notranslate">pow(-9, 0.5)</code> returns a value close to <code class="docutils literal notranslate">3j</code>. Whereas, for a negative base of type <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> or <a class="reference internal" href="#float" title="float"><code class="xref py py-class docutils literal notranslate">float</code></a> with an integral exponent, a float result is delivered. For example, <code class="docutils literal notranslate">pow(-9, 2.0)</code> returns <code class="docutils literal notranslate">81.0</code>. For <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> operands base and exp, if mod is present, mod must also be of integer type and mod must be nonzero. If mod is present and exp is negative, base must be relatively prime to mod. In that case, <code class="docutils literal notranslate">pow(inv_base, -exp, mod)</code> is returned, where inv_base is an inverse to base modulo mod. Here’s an example of computing an inverse for <code class="docutils literal notranslate">38</code> modulo <code class="docutils literal notranslate">97</code>: <div class="highlight-python3 notranslate"><div class="highlight"><pre>>>> pow(38, -1, mod=97) 23 >>> 23 * 38 % 97 == 1 True </pre></div> </div> <div class="versionchanged"> Changed in version 3.8: For <a class="reference internal" href="#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> operands, the three-argument form of <code class="docutils literal notranslate">pow</code> now allows the second argument to be negative, permitting computation of modular inverses. </div> <div class="versionchanged"> Changed in version 3.8: Allow keyword arguments. Formerly, only positional arguments were supported. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="print"> print(*objects, sep=' ', end='\n', file=None, flush=False)<a class="headerlink" href="#print" title="Link to this definition">¶</a></dt> <dd>Print objects to the text stream file, separated by sep and followed by end. sep, end, file, and flush, if present, must be given as keyword arguments. All non-keyword arguments are converted to strings like <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-func docutils literal notranslate">str()</code></a> does and written to the stream, separated by sep and followed by end. Both sep and end must be strings; they can also be <code class="docutils literal notranslate">None</code>, which means to use the default values. If no objects are given, <a class="reference internal" href="#print" title="print"><code class="xref py py-func docutils literal notranslate">print()</code></a> will just write end. The file argument must be an object with a <code class="docutils literal notranslate">write(string)</code> method; if it is not present or <code class="docutils literal notranslate">None</code>, <a class="reference internal" href="sys.html#sys.stdout" title="sys.stdout"><code class="xref py py-data docutils literal notranslate">sys.stdout</code></a> will be used. Since printed arguments are converted to text strings, <a class="reference internal" href="#print" title="print"><code class="xref py py-func docutils literal notranslate">print()</code></a> cannot be used with binary mode file objects. For these, use <code class="docutils literal notranslate">file.write(...)</code> instead. Output buffering is usually determined by file. However, if flush is true, the stream is forcibly flushed. <div class="versionchanged"> Changed in version 3.3: Added the flush keyword argument. </div> </dd></dl> <dl class="py class"> <dt class="sig sig-object py" id="property"> class property(fget=None, fset=None, fdel=None, doc=None)<a class="headerlink" href="#property" title="Link to this definition">¶</a></dt> <dd>Return a property attribute. fget is a function for getting an attribute value. fset is a function for setting an attribute value. fdel is a function for deleting an attribute value. And doc creates a docstring for the attribute. A typical use is to define a managed attribute <code class="docutils literal notranslate">x</code>: <div class="highlight-python3 notranslate"><div class="highlight"><pre>class C: def __init__(self): self._x = None def getx(self): return self._x def setx(self, value): self._x = value def delx(self): del self._x x = property(getx, setx, delx, "I'm the 'x' property.") </pre></div> </div> If c is an instance of C, <code class="docutils literal notranslate">c.x</code> will invoke the getter, <code class="docutils literal notranslate">c.x = value</code> will invoke the setter, and <code class="docutils literal notranslate">del c.x</code> the deleter. If given, doc will be the docstring of the property attribute. Otherwise, the property will copy fget’s docstring (if it exists). This makes it possible to create read-only properties easily using <a class="reference internal" href="#property" title="property"><code class="xref py py-func docutils literal notranslate">property()</code></a> as a <a class="reference internal" href="../glossary.html#term-decorator">decorator</a>: <div class="highlight-python3 notranslate"><div class="highlight"><pre>class Parrot: def __init__(self): self._voltage = 100000 @property def voltage(self): """Get the current voltage.""" return self._voltage </pre></div> </div> The <code class="docutils literal notranslate">@property</code> decorator turns the <code class="xref py py-meth docutils literal notranslate">voltage()</code> method into a “getter” for a read-only attribute with the same name, and it sets the docstring for voltage to “Get the current voltage.” <dl class="py function"> <dt class="sig sig-object py" id="property.getter"> @getter<a class="headerlink" href="#property.getter" title="Link to this definition">¶</a></dt> <dd></dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="property.setter"> @setter<a class="headerlink" href="#property.setter" title="Link to this definition">¶</a></dt> <dd></dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="property.deleter"> @deleter<a class="headerlink" href="#property.deleter" title="Link to this definition">¶</a></dt> <dd>A property object has <code class="docutils literal notranslate">getter</code>, <code class="docutils literal notranslate">setter</code>, and <code class="docutils literal notranslate">deleter</code> methods usable as decorators that create a copy of the property with the corresponding accessor function set to the decorated function. This is best explained with an example: <div class="highlight-python notranslate"><div class="highlight"><pre>class C: def __init__(self): self._x = None @property def x(self): """I'm the 'x' property.""" return self._x @x.setter def x(self, value): self._x = value @x.deleter def x(self): del self._x </pre></div> </div> This code is exactly equivalent to the first example. Be sure to give the additional functions the same name as the original property (<code class="docutils literal notranslate">x</code> in this case.) The returned property object also has the attributes <code class="docutils literal notranslate">fget</code>, <code class="docutils literal notranslate">fset</code>, and <code class="docutils literal notranslate">fdel</code> corresponding to the constructor arguments. </dd></dl> <div class="versionchanged"> Changed in version 3.5: The docstrings of property objects are now writeable. </div> <dl class="py attribute"> <dt class="sig sig-object py" id="property.__name__"> __name__<a class="headerlink" href="#property.__name__" title="Link to this definition">¶</a></dt> <dd>Attribute holding the name of the property. The name of the property can be changed at runtime. <div class="versionadded"> Added in version 3.13. </div> </dd></dl> </dd></dl> <dl class="py class" id="func-range"> <dt class="sig sig-object py"> class range(stop)</dt> <dt class="sig sig-object py"> class range(start, stop, step=1)</dt> <dd>Rather than being a function, <a class="reference internal" href="stdtypes.html#range" title="range"><code class="xref py py-class docutils literal notranslate">range</code></a> is actually an immutable sequence type, as documented in <a class="reference internal" href="stdtypes.html#typesseq-range">Ranges</a> and <a class="reference internal" href="stdtypes.html#typesseq">Sequence Types — list, tuple, range</a>. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="repr"> repr(object)<a class="headerlink" href="#repr" title="Link to this definition">¶</a></dt> <dd>Return a string containing a printable representation of an object. For many types, this function makes an attempt to return a string that would yield an object with the same value when passed to <a class="reference internal" href="#eval" title="eval"><code class="xref py py-func docutils literal notranslate">eval()</code></a>; otherwise, the representation is a string enclosed in angle brackets that contains the name of the type of the object together with additional information often including the name and address of the object. A class can control what this function returns for its instances by defining a <a class="reference internal" href="../reference/datamodel.html#object.__repr__" title="object.__repr__"><code class="xref py py-meth docutils literal notranslate">__repr__()</code></a> method. If <a class="reference internal" href="sys.html#sys.displayhook" title="sys.displayhook"><code class="xref py py-func docutils literal notranslate">sys.displayhook()</code></a> is not accessible, this function will raise <a class="reference internal" href="exceptions.html#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate">RuntimeError</code></a>. This class has a custom representation that can be evaluated: <div class="highlight-python3 notranslate"><div class="highlight"><pre>class Person: def __init__(self, name, age): self.name = name self.age = age def __repr__(self): return f"Person('{self.name}', {self.age})" </pre></div> </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="reversed"> reversed(seq)<a class="headerlink" href="#reversed" title="Link to this definition">¶</a></dt> <dd>Return a reverse <a class="reference internal" href="../glossary.html#term-iterator">iterator</a>. seq must be an object which has a <a class="reference internal" href="../reference/datamodel.html#object.__reversed__" title="object.__reversed__"><code class="xref py py-meth docutils literal notranslate">__reversed__()</code></a> method or supports the sequence protocol (the <a class="reference internal" href="../reference/datamodel.html#object.__len__" title="object.__len__"><code class="xref py py-meth docutils literal notranslate">__len__()</code></a> method and the <a class="reference internal" href="../reference/datamodel.html#object.__getitem__" title="object.__getitem__"><code class="xref py py-meth docutils literal notranslate">__getitem__()</code></a> method with integer arguments starting at <code class="docutils literal notranslate">0</code>). </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="round"> round(number, ndigits=None)<a class="headerlink" href="#round" title="Link to this definition">¶</a></dt> <dd>Return number rounded to ndigits precision after the decimal point. If ndigits is omitted or is <code class="docutils literal notranslate">None</code>, it returns the nearest integer to its input. For the built-in types supporting <a class="reference internal" href="#round" title="round"><code class="xref py py-func docutils literal notranslate">round()</code></a>, values are rounded to the closest multiple of 10 to the power minus ndigits; if two multiples are equally close, rounding is done toward the even choice (so, for example, both <code class="docutils literal notranslate">round(0.5)</code> and <code class="docutils literal notranslate">round(-0.5)</code> are <code class="docutils literal notranslate">0</code>, and <code class="docutils literal notranslate">round(1.5)</code> is <code class="docutils literal notranslate">2</code>). Any integer value is valid for ndigits (positive, zero, or negative). The return value is an integer if ndigits is omitted or <code class="docutils literal notranslate">None</code>. Otherwise, the return value has the same type as number. For a general Python object <code class="docutils literal notranslate">number</code>, <code class="docutils literal notranslate">round</code> delegates to <code class="docutils literal notranslate">number.__round__</code>. <div class="admonition note"> Note The behavior of <a class="reference internal" href="#round" title="round"><code class="xref py py-func docutils literal notranslate">round()</code></a> for floats can be surprising: for example, <code class="docutils literal notranslate">round(2.675, 2)</code> gives <code class="docutils literal notranslate">2.67</code> instead of the expected <code class="docutils literal notranslate">2.68</code>. This is not a bug: it’s a result of the fact that most decimal fractions can’t be represented exactly as a float. See <a class="reference internal" href="../tutorial/floatingpoint.html#tut-fp-issues">Floating-Point Arithmetic: Issues and Limitations</a> for more information. </div> </dd></dl> <dl class="py class" id="func-set"> <dt class="sig sig-object py"> class set</dt> <dt class="sig sig-object py"> class set(iterable)</dt> <dd>Return a new <a class="reference internal" href="stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate">set</code></a> object, optionally with elements taken from iterable. <code class="docutils literal notranslate">set</code> is a built-in class. See <a class="reference internal" href="stdtypes.html#set" title="set"><code class="xref py py-class docutils literal notranslate">set</code></a> and <a class="reference internal" href="stdtypes.html#types-set">Set Types — set, frozenset</a> for documentation about this class. For other containers see the built-in <a class="reference internal" href="stdtypes.html#frozenset" title="frozenset"><code class="xref py py-class docutils literal notranslate">frozenset</code></a>, <a class="reference internal" href="stdtypes.html#list" title="list"><code class="xref py py-class docutils literal notranslate">list</code></a>, <a class="reference internal" href="stdtypes.html#tuple" title="tuple"><code class="xref py py-class docutils literal notranslate">tuple</code></a>, and <a class="reference internal" href="stdtypes.html#dict" title="dict"><code class="xref py py-class docutils literal notranslate">dict</code></a> classes, as well as the <a class="reference internal" href="collections.html#module-collections" title="collections: Container datatypes"><code class="xref py py-mod docutils literal notranslate">collections</code></a> module. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="setattr"> setattr(object, name, value)<a class="headerlink" href="#setattr" title="Link to this definition">¶</a></dt> <dd>This is the counterpart of <a class="reference internal" href="#getattr" title="getattr"><code class="xref py py-func docutils literal notranslate">getattr()</code></a>. The arguments are an object, a string, and an arbitrary value. The string may name an existing attribute or a new attribute. The function assigns the value to the attribute, provided the object allows it. For example, <code class="docutils literal notranslate">setattr(x, 'foobar', 123)</code> is equivalent to <code class="docutils literal notranslate">x.foobar = 123</code>. name need not be a Python identifier as defined in <a class="reference internal" href="../reference/lexical_analysis.html#identifiers">Identifiers and keywords</a> unless the object chooses to enforce that, for example in a custom <a class="reference internal" href="../reference/datamodel.html#object.__getattribute__" title="object.__getattribute__"><code class="xref py py-meth docutils literal notranslate">__getattribute__()</code></a> or via <a class="reference internal" href="../reference/datamodel.html#object.__slots__" title="object.__slots__"><code class="xref py py-attr docutils literal notranslate">__slots__</code></a>. An attribute whose name is not an identifier will not be accessible using the dot notation, but is accessible through <a class="reference internal" href="#getattr" title="getattr"><code class="xref py py-func docutils literal notranslate">getattr()</code></a> etc.. <div class="admonition note"> Note Since <a class="reference internal" href="../reference/expressions.html#private-name-mangling">private name mangling</a> happens at compilation time, one must manually mangle a private attribute’s (attributes with two leading underscores) name in order to set it with <a class="reference internal" href="#setattr" title="setattr"><code class="xref py py-func docutils literal notranslate">setattr()</code></a>. </div> </dd></dl> <dl class="py class"> <dt class="sig sig-object py" id="slice"> class slice(stop)<a class="headerlink" href="#slice" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> class slice(start, stop, step=None)</dt> <dd>Return a <a class="reference internal" href="../glossary.html#term-slice">slice</a> object representing the set of indices specified by <code class="docutils literal notranslate">range(start, stop, step)</code>. The start and step arguments default to <code class="docutils literal notranslate">None</code>. <dl class="py attribute"> <dt class="sig sig-object py" id="slice.start"> start<a class="headerlink" href="#slice.start" title="Link to this definition">¶</a></dt> <dd></dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="slice.stop"> stop<a class="headerlink" href="#slice.stop" title="Link to this definition">¶</a></dt> <dd></dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="slice.step"> step<a class="headerlink" href="#slice.step" title="Link to this definition">¶</a></dt> <dd>Slice objects have read-only data attributes <code class="xref py py-attr docutils literal notranslate">start</code>, <code class="xref py py-attr docutils literal notranslate">stop</code>, and <code class="xref py py-attr docutils literal notranslate">step</code> which merely return the argument values (or their default). They have no other explicit functionality; however, they are used by NumPy and other third-party packages. </dd></dl> Slice objects are also generated when extended indexing syntax is used. For example: <code class="docutils literal notranslate">a[start:stop:step]</code> or <code class="docutils literal notranslate">a[start:stop, i]</code>. See <a class="reference internal" href="itertools.html#itertools.islice" title="itertools.islice"><code class="xref py py-func docutils literal notranslate">itertools.islice()</code></a> for an alternate version that returns an <a class="reference internal" href="../glossary.html#term-iterator">iterator</a>. <div class="versionchanged"> Changed in version 3.12: Slice objects are now <a class="reference internal" href="../glossary.html#term-hashable">hashable</a> (provided <a class="reference internal" href="#slice.start" title="slice.start"><code class="xref py py-attr docutils literal notranslate">start</code></a>, <a class="reference internal" href="#slice.stop" title="slice.stop"><code class="xref py py-attr docutils literal notranslate">stop</code></a>, and <a class="reference internal" href="#slice.step" title="slice.step"><code class="xref py py-attr docutils literal notranslate">step</code></a> are hashable). </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="sorted"> sorted(iterable, /, *, key=None, reverse=False)<a class="headerlink" href="#sorted" title="Link to this definition">¶</a></dt> <dd>Return a new sorted list from the items in iterable. Has two optional arguments which must be specified as keyword arguments. key specifies a function of one argument that is used to extract a comparison key from each element in iterable (for example, <code class="docutils literal notranslate">key=str.lower</code>). The default value is <code class="docutils literal notranslate">None</code> (compare the elements directly). reverse is a boolean value. If set to <code class="docutils literal notranslate">True</code>, then the list elements are sorted as if each comparison were reversed. Use <a class="reference internal" href="functools.html#functools.cmp_to_key" title="functools.cmp_to_key"><code class="xref py py-func docutils literal notranslate">functools.cmp_to_key()</code></a> to convert an old-style cmp function to a key function. The built-in <a class="reference internal" href="#sorted" title="sorted"><code class="xref py py-func docutils literal notranslate">sorted()</code></a> function is guaranteed to be stable. A sort is stable if it guarantees not to change the relative order of elements that compare equal — this is helpful for sorting in multiple passes (for example, sort by department, then by salary grade). The sort algorithm uses only <code class="docutils literal notranslate"><</code> comparisons between items. While defining an <a class="reference internal" href="../reference/datamodel.html#object.__lt__" title="object.__lt__"><code class="xref py py-meth docutils literal notranslate">__lt__()</code></a> method will suffice for sorting, <a class="pep reference external" href="https://peps.python.org/pep-0008/">PEP 8</a> recommends that all six <a class="reference internal" href="../reference/expressions.html#comparisons">rich comparisons</a> be implemented. This will help avoid bugs when using the same data with other ordering tools such as <a class="reference internal" href="#max" title="max"><code class="xref py py-func docutils literal notranslate">max()</code></a> that rely on a different underlying method. Implementing all six comparisons also helps avoid confusion for mixed type comparisons which can call reflected the <a class="reference internal" href="../reference/datamodel.html#object.__gt__" title="object.__gt__"><code class="xref py py-meth docutils literal notranslate">__gt__()</code></a> method. For sorting examples and a brief sorting tutorial, see <a class="reference internal" href="../howto/sorting.html#sortinghowto">Sorting Techniques</a>. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="staticmethod"> @staticmethod<a class="headerlink" href="#staticmethod" title="Link to this definition">¶</a></dt> <dd>Transform a method into a static method. A static method does not receive an implicit first argument. To declare a static method, use this idiom: <div class="highlight-python3 notranslate"><div class="highlight"><pre>class C: @staticmethod def f(arg1, arg2, argN): ... </pre></div> </div> The <code class="docutils literal notranslate">@staticmethod</code> form is a function <a class="reference internal" href="../glossary.html#term-decorator">decorator</a> – see <a class="reference internal" href="../reference/compound_stmts.html#function">Function definitions</a> for details. A static method can be called either on the class (such as <code class="docutils literal notranslate">C.f()</code>) or on an instance (such as <code class="docutils literal notranslate">C().f()</code>). Moreover, the static method <a class="reference internal" href="../glossary.html#term-descriptor">descriptor</a> is also callable, so it can be used in the class definition (such as <code class="docutils literal notranslate">f()</code>). Static methods in Python are similar to those found in Java or C++. Also, see <a class="reference internal" href="#classmethod" title="classmethod"><code class="xref py py-func docutils literal notranslate">classmethod()</code></a> for a variant that is useful for creating alternate class constructors. Like all decorators, it is also possible to call <code class="docutils literal notranslate">staticmethod</code> as a regular function and do something with its result. This is needed in some cases where you need a reference to a function from a class body and you want to avoid the automatic transformation to instance method. For these cases, use this idiom: <div class="highlight-python3 notranslate"><div class="highlight"><pre>def regular_function(): ... class C: method = staticmethod(regular_function) </pre></div> </div> For more information on static methods, see <a class="reference internal" href="../reference/datamodel.html#types">The standard type hierarchy</a>. <div class="versionchanged"> Changed in version 3.10: Static methods now inherit the method attributes (<a class="reference internal" href="../reference/datamodel.html#function.__module__" title="function.__module__"><code class="xref py py-attr docutils literal notranslate">__module__</code></a>, <a class="reference internal" href="../reference/datamodel.html#function.__name__" title="function.__name__"><code class="xref py py-attr docutils literal notranslate">__name__</code></a>, <a class="reference internal" href="../reference/datamodel.html#function.__qualname__" title="function.__qualname__"><code class="xref py py-attr docutils literal notranslate">__qualname__</code></a>, <a class="reference internal" href="../reference/datamodel.html#function.__doc__" title="function.__doc__"><code class="xref py py-attr docutils literal notranslate">__doc__</code></a> and <a class="reference internal" href="../reference/datamodel.html#function.__annotations__" title="function.__annotations__"><code class="xref py py-attr docutils literal notranslate">__annotations__</code></a>), have a new <code class="docutils literal notranslate">__wrapped__</code> attribute, and are now callable as regular functions. </div> </dd></dl> <dl class="py class" id="func-str"> <dt class="sig sig-object py"> class str(object='')</dt> <dt class="sig sig-object py"> class str(object=b'', encoding='utf-8', errors='strict')</dt> <dd>Return a <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-class docutils literal notranslate">str</code></a> version of object. See <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-func docutils literal notranslate">str()</code></a> for details. <code class="docutils literal notranslate">str</code> is the built-in string <a class="reference internal" href="../glossary.html#term-class">class</a>. For general information about strings, see <a class="reference internal" href="stdtypes.html#textseq">Text Sequence Type — str</a>. </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="sum"> sum(iterable, /, start=0)<a class="headerlink" href="#sum" title="Link to this definition">¶</a></dt> <dd>Sums start and the items of an iterable from left to right and returns the total. The iterable’s items are normally numbers, and the start value is not allowed to be a string. For some use cases, there are good alternatives to <a class="reference internal" href="#sum" title="sum"><code class="xref py py-func docutils literal notranslate">sum()</code></a>. The preferred, fast way to concatenate a sequence of strings is by calling <code class="docutils literal notranslate">''.join(sequence)</code>. To add floating-point values with extended precision, see <a class="reference internal" href="math.html#math.fsum" title="math.fsum"><code class="xref py py-func docutils literal notranslate">math.fsum()</code></a>. To concatenate a series of iterables, consider using <a class="reference internal" href="itertools.html#itertools.chain" title="itertools.chain"><code class="xref py py-func docutils literal notranslate">itertools.chain()</code></a>. <div class="versionchanged"> Changed in version 3.8: The start parameter can be specified as a keyword argument. </div> <div class="versionchanged"> Changed in version 3.12: Summation of floats switched to an algorithm that gives higher accuracy and better commutativity on most builds. </div> </dd></dl> <dl class="py class"> <dt class="sig sig-object py" id="super"> class super<a class="headerlink" href="#super" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> class super(type, object_or_type=None)</dt> <dd>Return a proxy object that delegates method calls to a parent or sibling class of type. This is useful for accessing inherited methods that have been overridden in a class. The object_or_type determines the <a class="reference internal" href="../glossary.html#term-method-resolution-order">method resolution order</a> to be searched. The search starts from the class right after the type. For example, if <a class="reference internal" href="../reference/datamodel.html#type.__mro__" title="type.__mro__"><code class="xref py py-attr docutils literal notranslate">__mro__</code></a> of object_or_type is <code class="docutils literal notranslate">D -> B -> C -> A -> object</code> and the value of type is <code class="docutils literal notranslate">B</code>, then <a class="reference internal" href="#super" title="super"><code class="xref py py-func docutils literal notranslate">super()</code></a> searches <code class="docutils literal notranslate">C -> A -> object</code>. The <a class="reference internal" href="../reference/datamodel.html#type.__mro__" title="type.__mro__"><code class="xref py py-attr docutils literal notranslate">__mro__</code></a> attribute of the class corresponding to object_or_type lists the method resolution search order used by both <a class="reference internal" href="#getattr" title="getattr"><code class="xref py py-func docutils literal notranslate">getattr()</code></a> and <a class="reference internal" href="#super" title="super"><code class="xref py py-func docutils literal notranslate">super()</code></a>. The attribute is dynamic and can change whenever the inheritance hierarchy is updated. If the second argument is omitted, the super object returned is unbound. If the second argument is an object, <code class="docutils literal notranslate">isinstance(obj, type)</code> must be true. If the second argument is a type, <code class="docutils literal notranslate">issubclass(type2, type)</code> must be true (this is useful for classmethods). When called directly within an ordinary method of a class, both arguments may be omitted (“zero-argument <code class="xref py py-func docutils literal notranslate">super()</code>”). In this case, type will be the enclosing class, and obj will be the first argument of the immediately enclosing function (typically <code class="docutils literal notranslate">self</code>). (This means that zero-argument <code class="xref py py-func docutils literal notranslate">super()</code> will not work as expected within nested functions, including generator expressions, which implicitly create nested functions.) There are two typical use cases for super. In a class hierarchy with single inheritance, super can be used to refer to parent classes without naming them explicitly, thus making the code more maintainable. This use closely parallels the use of super in other programming languages. The second use case is to support cooperative multiple inheritance in a dynamic execution environment. This use case is unique to Python and is not found in statically compiled languages or languages that only support single inheritance. This makes it possible to implement “diamond diagrams” where multiple base classes implement the same method. Good design dictates that such implementations have the same calling signature in every case (because the order of calls is determined at runtime, because that order adapts to changes in the class hierarchy, and because that order can include sibling classes that are unknown prior to runtime). For both use cases, a typical superclass call looks like this: <div class="highlight-python3 notranslate"><div class="highlight"><pre>class C(B): def method(self, arg): super().method(arg) # This does the same thing as: # super(C, self).method(arg) </pre></div> </div> In addition to method lookups, <a class="reference internal" href="#super" title="super"><code class="xref py py-func docutils literal notranslate">super()</code></a> also works for attribute lookups. One possible use case for this is calling <a class="reference internal" href="../glossary.html#term-descriptor">descriptors</a> in a parent or sibling class. Note that <a class="reference internal" href="#super" title="super"><code class="xref py py-func docutils literal notranslate">super()</code></a> is implemented as part of the binding process for explicit dotted attribute lookups such as <code class="docutils literal notranslate">super().__getitem__(name)</code>. It does so by implementing its own <a class="reference internal" href="../reference/datamodel.html#object.__getattribute__" title="object.__getattribute__"><code class="xref py py-meth docutils literal notranslate">__getattribute__()</code></a> method for searching classes in a predictable order that supports cooperative multiple inheritance. Accordingly, <a class="reference internal" href="#super" title="super"><code class="xref py py-func docutils literal notranslate">super()</code></a> is undefined for implicit lookups using statements or operators such as <code class="docutils literal notranslate">super()[name]</code>. Also note that, aside from the zero argument form, <a class="reference internal" href="#super" title="super"><code class="xref py py-func docutils literal notranslate">super()</code></a> is not limited to use inside methods. The two argument form specifies the arguments exactly and makes the appropriate references. The zero argument form only works inside a class definition, as the compiler fills in the necessary details to correctly retrieve the class being defined, as well as accessing the current instance for ordinary methods. For practical suggestions on how to design cooperative classes using <a class="reference internal" href="#super" title="super"><code class="xref py py-func docutils literal notranslate">super()</code></a>, see <a class="reference external" href="https://rhettinger.wordpress.com/2011/05/26/super-considered-super/">guide to using super()</a>. </dd></dl> <dl class="py class" id="func-tuple"> <dt class="sig sig-object py"> class tuple</dt> <dt class="sig sig-object py"> class tuple(iterable)</dt> <dd>Rather than being a function, <a class="reference internal" href="stdtypes.html#tuple" title="tuple"><code class="xref py py-class docutils literal notranslate">tuple</code></a> is actually an immutable sequence type, as documented in <a class="reference internal" href="stdtypes.html#typesseq-tuple">Tuples</a> and <a class="reference internal" href="stdtypes.html#typesseq">Sequence Types — list, tuple, range</a>. </dd></dl> <dl class="py class"> <dt class="sig sig-object py" id="type"> class type(object)<a class="headerlink" href="#type" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> class type(name, bases, dict, **kwds)</dt> <dd>With one argument, return the type of an object. The return value is a type object and generally the same object as returned by <a class="reference internal" href="../reference/datamodel.html#object.__class__" title="object.__class__"><code class="xref py py-attr docutils literal notranslate">object.__class__</code></a>. The <a class="reference internal" href="#isinstance" title="isinstance"><code class="xref py py-func docutils literal notranslate">isinstance()</code></a> built-in function is recommended for testing the type of an object, because it takes subclasses into account. With three arguments, return a new type object. This is essentially a dynamic form of the <a class="reference internal" href="../reference/compound_stmts.html#class"><code class="xref std std-keyword docutils literal notranslate">class</code></a> statement. The name string is the class name and becomes the <a class="reference internal" href="../reference/datamodel.html#type.__name__" title="type.__name__"><code class="xref py py-attr docutils literal notranslate">__name__</code></a> attribute. The bases tuple contains the base classes and becomes the <a class="reference internal" href="../reference/datamodel.html#type.__bases__" title="type.__bases__"><code class="xref py py-attr docutils literal notranslate">__bases__</code></a> attribute; if empty, <a class="reference internal" href="#object" title="object"><code class="xref py py-class docutils literal notranslate">object</code></a>, the ultimate base of all classes, is added. The dict dictionary contains attribute and method definitions for the class body; it may be copied or wrapped before becoming the <a class="reference internal" href="../reference/datamodel.html#type.__dict__" title="type.__dict__"><code class="xref py py-attr docutils literal notranslate">__dict__</code></a> attribute. The following two statements create identical <code class="xref py py-class docutils literal notranslate">type</code> objects: <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> class X: ... a = 1 ... >>> X = type('X', (), dict(a=1)) </pre></div> </div> See also: <ul class="simple"> <li><a class="reference internal" href="../reference/datamodel.html#class-attrs-and-methods">Documentation on attributes and methods on classes</a>.</li> <li><a class="reference internal" href="stdtypes.html#bltin-type-objects">Type Objects</a></li> </ul> Keyword arguments provided to the three argument form are passed to the appropriate metaclass machinery (usually <a class="reference internal" href="../reference/datamodel.html#object.__init_subclass__" title="object.__init_subclass__"><code class="xref py py-meth docutils literal notranslate">__init_subclass__()</code></a>) in the same way that keywords in a class definition (besides metaclass) would. See also <a class="reference internal" href="../reference/datamodel.html#class-customization">Customizing class creation</a>. <div class="versionchanged"> Changed in version 3.6: Subclasses of <code class="xref py py-class docutils literal notranslate">type</code> which don’t override <code class="docutils literal notranslate">type.__new__</code> may no longer use the one-argument form to get the type of an object. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="vars"> vars()<a class="headerlink" href="#vars" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> vars(object)</dt> <dd>Return the <a class="reference internal" href="../reference/datamodel.html#object.__dict__" title="object.__dict__"><code class="xref py py-attr docutils literal notranslate">__dict__</code></a> attribute for a module, class, instance, or any other object with a <code class="xref py py-attr docutils literal notranslate">__dict__</code> attribute. Objects such as modules and instances have an updateable <a class="reference internal" href="../reference/datamodel.html#object.__dict__" title="object.__dict__"><code class="xref py py-attr docutils literal notranslate">__dict__</code></a> attribute; however, other objects may have write restrictions on their <code class="xref py py-attr docutils literal notranslate">__dict__</code> attributes (for example, classes use a <a class="reference internal" href="types.html#types.MappingProxyType" title="types.MappingProxyType"><code class="xref py py-class docutils literal notranslate">types.MappingProxyType</code></a> to prevent direct dictionary updates). Without an argument, <a class="reference internal" href="#vars" title="vars"><code class="xref py py-func docutils literal notranslate">vars()</code></a> acts like <a class="reference internal" href="#locals" title="locals"><code class="xref py py-func docutils literal notranslate">locals()</code></a>. A <a class="reference internal" href="exceptions.html#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> exception is raised if an object is specified but it doesn’t have a <a class="reference internal" href="../reference/datamodel.html#object.__dict__" title="object.__dict__"><code class="xref py py-attr docutils literal notranslate">__dict__</code></a> attribute (for example, if its class defines the <a class="reference internal" href="../reference/datamodel.html#object.__slots__" title="object.__slots__"><code class="xref py py-attr docutils literal notranslate">__slots__</code></a> attribute). <div class="versionchanged"> Changed in version 3.13: The result of calling this function without an argument has been updated as described for the <a class="reference internal" href="#locals" title="locals"><code class="xref py py-func docutils literal notranslate">locals()</code></a> builtin. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="zip"> zip(*iterables, strict=False)<a class="headerlink" href="#zip" title="Link to this definition">¶</a></dt> <dd>Iterate over several iterables in parallel, producing tuples with an item from each one. Example: <div class="highlight-python3 notranslate"><div class="highlight"><pre>>>> for item in zip([1, 2, 3], ['sugar', 'spice', 'everything nice']): ... print(item) ... (1, 'sugar') (2, 'spice') (3, 'everything nice') </pre></div> </div> More formally: <a class="reference internal" href="#zip" title="zip"><code class="xref py py-func docutils literal notranslate">zip()</code></a> returns an iterator of tuples, where the i-th tuple contains the i-th element from each of the argument iterables. Another way to think of <a class="reference internal" href="#zip" title="zip"><code class="xref py py-func docutils literal notranslate">zip()</code></a> is that it turns rows into columns, and columns into rows. This is similar to <a class="reference external" href="https://en.wikipedia.org/wiki/Transpose">transposing a matrix</a>. <a class="reference internal" href="#zip" title="zip"><code class="xref py py-func docutils literal notranslate">zip()</code></a> is lazy: The elements won’t be processed until the iterable is iterated on, e.g. by a <code class="xref std std-keyword docutils literal notranslate">for</code> loop or by wrapping in a <a class="reference internal" href="stdtypes.html#list" title="list"><code class="xref py py-class docutils literal notranslate">list</code></a>. One thing to consider is that the iterables passed to <a class="reference internal" href="#zip" title="zip"><code class="xref py py-func docutils literal notranslate">zip()</code></a> could have different lengths; sometimes by design, and sometimes because of a bug in the code that prepared these iterables. Python offers three different approaches to dealing with this issue: <ul> <li>By default, <a class="reference internal" href="#zip" title="zip"><code class="xref py py-func docutils literal notranslate">zip()</code></a> stops when the shortest iterable is exhausted. It will ignore the remaining items in the longer iterables, cutting off the result to the length of the shortest iterable: <div class="highlight-python3 notranslate"><div class="highlight"><pre>>>> list(zip(range(3), ['fee', 'fi', 'fo', 'fum'])) [(0, 'fee'), (1, 'fi'), (2, 'fo')] </pre></div> </div> </li> <li><a class="reference internal" href="#zip" title="zip"><code class="xref py py-func docutils literal notranslate">zip()</code></a> is often used in cases where the iterables are assumed to be of equal length. In such cases, it’s recommended to use the <code class="docutils literal notranslate">strict=True</code> option. Its output is the same as regular <a class="reference internal" href="#zip" title="zip"><code class="xref py py-func docutils literal notranslate">zip()</code></a>: <div class="highlight-python3 notranslate"><div class="highlight"><pre>>>> list(zip(('a', 'b', 'c'), (1, 2, 3), strict=True)) [('a', 1), ('b', 2), ('c', 3)] </pre></div> </div> Unlike the default behavior, it raises a <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate">ValueError</code></a> if one iterable is exhausted before the others: <div class="doctest highlight-default notranslate"><div class="highlight"><pre>>>> for item in zip(range(3), ['fee', 'fi', 'fo', 'fum'], strict=True): ... print(item) ... (0, 'fee') (1, 'fi') (2, 'fo') Traceback (most recent call last): ... ValueError: zip() argument 2 is longer than argument 1 </pre></div> </div> Without the <code class="docutils literal notranslate">strict=True</code> argument, any bug that results in iterables of different lengths will be silenced, possibly manifesting as a hard-to-find bug in another part of the program. </li> <li>Shorter iterables can be padded with a constant value to make all the iterables have the same length. This is done by <a class="reference internal" href="itertools.html#itertools.zip_longest" title="itertools.zip_longest"><code class="xref py py-func docutils literal notranslate">itertools.zip_longest()</code></a>.</li> </ul> Edge cases: With a single iterable argument, <a class="reference internal" href="#zip" title="zip"><code class="xref py py-func docutils literal notranslate">zip()</code></a> returns an iterator of 1-tuples. With no arguments, it returns an empty iterator. Tips and tricks: <ul> <li>The left-to-right evaluation order of the iterables is guaranteed. This makes possible an idiom for clustering a data series into n-length groups using <code class="docutils literal notranslate">zip(*[iter(s)]*n, strict=True)</code>. This repeats the same iterator <code class="docutils literal notranslate">n</code> times so that each output tuple has the result of <code class="docutils literal notranslate">n</code> calls to the iterator. This has the effect of dividing the input into n-length chunks.</li> <li><a class="reference internal" href="#zip" title="zip"><code class="xref py py-func docutils literal notranslate">zip()</code></a> in conjunction with the <code class="docutils literal notranslate">*</code> operator can be used to unzip a list: <div class="highlight-python3 notranslate"><div class="highlight"><pre>>>> x = [1, 2, 3] >>> y = [4, 5, 6] >>> list(zip(x, y)) [(1, 4), (2, 5), (3, 6)] >>> x2, y2 = zip(*zip(x, y)) >>> x == list(x2) and y == list(y2) True </pre></div> </div> </li> </ul> <div class="versionchanged"> Changed in version 3.10: Added the <code class="docutils literal notranslate">strict</code> argument. </div> </dd></dl> <dl class="py function"> <dt class="sig sig-object py" id="import__"> __import__(name, globals=None, locals=None, fromlist=(), level=0)<a class="headerlink" href="#import__" title="Link to this definition">¶</a></dt> <dd><div class="admonition note" id="index-15"> Note This is an advanced function that is not needed in everyday Python programming, unlike <a class="reference internal" href="importlib.html#importlib.import_module" title="importlib.import_module"><code class="xref py py-func docutils literal notranslate">importlib.import_module()</code></a>. </div> This function is invoked by the <a class="reference internal" href="../reference/simple_stmts.html#import"><code class="xref std std-keyword docutils literal notranslate">import</code></a> statement. It can be replaced (by importing the <a class="reference internal" href="builtins.html#module-builtins" title="builtins: The module that provides the built-in namespace."><code class="xref py py-mod docutils literal notranslate">builtins</code></a> module and assigning to <code class="docutils literal notranslate">builtins.__import__</code>) in order to change semantics of the <code class="xref std std-keyword docutils literal notranslate">import</code> statement, but doing so is strongly discouraged as it is usually simpler to use import hooks (see <a class="pep reference external" href="https://peps.python.org/pep-0302/">PEP 302</a>) to attain the same goals and does not cause issues with code which assumes the default import implementation is in use. Direct use of <a class="reference internal" href="#import__" title="__import__"><code class="xref py py-func docutils literal notranslate">__import__()</code></a> is also discouraged in favor of <a class="reference internal" href="importlib.html#importlib.import_module" title="importlib.import_module"><code class="xref py py-func docutils literal notranslate">importlib.import_module()</code></a>. The function imports the module name, potentially using the given globals and locals to determine how to interpret the name in a package context. The fromlist gives the names of objects or submodules that should be imported from the module given by name. The standard implementation does not use its locals argument at all and uses its globals only to determine the package context of the <a class="reference internal" href="../reference/simple_stmts.html#import"><code class="xref std std-keyword docutils literal notranslate">import</code></a> statement. level specifies whether to use absolute or relative imports. <code class="docutils literal notranslate">0</code> (the default) means only perform absolute imports. Positive values for level indicate the number of parent directories to search relative to the directory of the module calling <a class="reference internal" href="#import__" title="__import__"><code class="xref py py-func docutils literal notranslate">__import__()</code></a> (see <a class="pep reference external" href="https://peps.python.org/pep-0328/">PEP 328</a> for the details). When the name variable is of the form <code class="docutils literal notranslate">package.module</code>, normally, the top-level package (the name up till the first dot) is returned, not the module named by name. However, when a non-empty fromlist argument is given, the module named by name is returned. For example, the statement <code class="docutils literal notranslate">import spam</code> results in bytecode resembling the following code: <div class="highlight-python3 notranslate"><div class="highlight"><pre>spam = __import__('spam', globals(), locals(), [], 0) </pre></div> </div> The statement <code class="docutils literal notranslate">import spam.ham</code> results in this call: <div class="highlight-python3 notranslate"><div class="highlight"><pre>spam = __import__('spam.ham', globals(), locals(), [], 0) </pre></div> </div> Note how <a class="reference internal" href="#import__" title="__import__"><code class="xref py py-func docutils literal notranslate">__import__()</code></a> returns the toplevel module here because this is the object that is bound to a name by the <a class="reference internal" href="../reference/simple_stmts.html#import"><code class="xref std std-keyword docutils literal notranslate">import</code></a> statement. On the other hand, the statement <code class="docutils literal notranslate">from spam.ham import eggs, sausage as saus</code> results in <div class="highlight-python3 notranslate"><div class="highlight"><pre>_temp = __import__('spam.ham', globals(), locals(), ['eggs', 'sausage'], 0) eggs = _temp.eggs saus = _temp.sausage </pre></div> </div> Here, the <code class="docutils literal notranslate">spam.ham</code> module is returned from <a class="reference internal" href="#import__" title="__import__"><code class="xref py py-func docutils literal notranslate">__import__()</code></a>. From this object, the names to import are retrieved and assigned to their respective names. If you simply want to import a module (potentially within a package) by name, use <a class="reference internal" href="importlib.html#importlib.import_module" title="importlib.import_module"><code class="xref py py-func docutils literal notranslate">importlib.import_module()</code></a>. <div class="versionchanged"> Changed in version 3.3: Negative values for level are no longer supported (which also changes the default value to 0). </div> <div class="versionchanged"> Changed in version 3.9: When the command line options <a class="reference internal" href="../using/cmdline.html#cmdoption-E"><code class="xref std std-option docutils literal notranslate">-E</code></a> or <a class="reference internal" href="../using/cmdline.html#cmdoption-I"><code class="xref std std-option docutils literal notranslate">-I</code></a> are being used, the environment variable <a class="reference internal" href="../using/cmdline.html#envvar-PYTHONCASEOK"><code class="xref std std-envvar docutils literal notranslate">PYTHONCASEOK</code></a> is now ignored. </div> </dd></dl> Footnotes <aside class="footnote-list brackets"> <aside class="footnote brackets" id="id2" role="doc-footnote"> [<a role="doc-backlink" href="#id1">1</a>] Note that the parser only accepts the Unix-style end of line convention. 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