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Contents</a></h3> <ul> <li><a class="reference internal" href="#">Built-in Exceptions</a><ul> <li><a class="reference internal" href="#exception-context">Exception context</a><ul> <li><a class="reference internal" href="#BaseException.__context__"><code class="docutils literal notranslate">__context__</code></a></li> <li><a class="reference internal" href="#BaseException.__cause__"><code class="docutils literal notranslate">__cause__</code></a></li> <li><a class="reference internal" href="#BaseException.__suppress_context__"><code class="docutils literal notranslate">__suppress_context__</code></a></li> </ul> </li> <li><a class="reference internal" href="#inheriting-from-built-in-exceptions">Inheriting from built-in exceptions</a></li> <li><a class="reference internal" href="#base-classes">Base classes</a><ul> <li><a class="reference internal" href="#BaseException"><code class="docutils literal notranslate">BaseException</code></a><ul> <li><a class="reference internal" href="#BaseException.args"><code class="docutils literal notranslate">args</code></a></li> <li><a class="reference internal" href="#BaseException.with_traceback"><code class="docutils literal notranslate">with_traceback()</code></a></li> <li><a class="reference internal" href="#BaseException.__traceback__"><code class="docutils literal notranslate">__traceback__</code></a></li> <li><a class="reference internal" href="#BaseException.add_note"><code class="docutils literal notranslate">add_note()</code></a></li> <li><a class="reference internal" href="#BaseException.__notes__"><code class="docutils literal notranslate">__notes__</code></a></li> </ul> </li> <li><a class="reference internal" href="#Exception"><code class="docutils literal notranslate">Exception</code></a></li> <li><a class="reference internal" href="#ArithmeticError"><code class="docutils literal notranslate">ArithmeticError</code></a></li> <li><a class="reference internal" href="#BufferError"><code class="docutils literal notranslate">BufferError</code></a></li> <li><a class="reference internal" href="#LookupError"><code class="docutils literal notranslate">LookupError</code></a></li> </ul> </li> <li><a class="reference internal" href="#concrete-exceptions">Concrete exceptions</a><ul> <li><a class="reference internal" href="#AssertionError"><code class="docutils literal notranslate">AssertionError</code></a></li> <li><a class="reference internal" href="#AttributeError"><code class="docutils literal notranslate">AttributeError</code></a></li> <li><a class="reference internal" href="#EOFError"><code class="docutils literal notranslate">EOFError</code></a></li> <li><a class="reference internal" href="#FloatingPointError"><code class="docutils literal notranslate">FloatingPointError</code></a></li> <li><a class="reference internal" href="#GeneratorExit"><code class="docutils literal notranslate">GeneratorExit</code></a></li> <li><a class="reference internal" href="#ImportError"><code class="docutils literal notranslate">ImportError</code></a><ul> <li><a class="reference internal" href="#ImportError.name"><code class="docutils literal notranslate">name</code></a></li> <li><a class="reference internal" href="#ImportError.path"><code class="docutils literal notranslate">path</code></a></li> </ul> </li> <li><a class="reference internal" href="#ModuleNotFoundError"><code class="docutils literal notranslate">ModuleNotFoundError</code></a></li> <li><a class="reference internal" href="#IndexError"><code class="docutils literal notranslate">IndexError</code></a></li> <li><a class="reference internal" href="#KeyError"><code class="docutils literal notranslate">KeyError</code></a></li> <li><a class="reference internal" href="#KeyboardInterrupt"><code class="docutils literal notranslate">KeyboardInterrupt</code></a></li> <li><a class="reference internal" href="#MemoryError"><code class="docutils literal notranslate">MemoryError</code></a></li> <li><a class="reference internal" href="#NameError"><code class="docutils literal notranslate">NameError</code></a></li> <li><a class="reference internal" href="#NotImplementedError"><code class="docutils literal notranslate">NotImplementedError</code></a></li> <li><a class="reference internal" href="#OSError"><code class="docutils literal notranslate">OSError</code></a><ul> <li><a class="reference internal" href="#OSError.errno"><code class="docutils literal notranslate">errno</code></a></li> <li><a class="reference internal" href="#OSError.winerror"><code class="docutils literal notranslate">winerror</code></a></li> <li><a class="reference internal" href="#OSError.strerror"><code class="docutils literal notranslate">strerror</code></a></li> <li><a class="reference internal" href="#OSError.filename"><code class="docutils literal notranslate">filename</code></a></li> <li><a class="reference internal" href="#OSError.filename2"><code class="docutils literal notranslate">filename2</code></a></li> </ul> </li> <li><a class="reference internal" href="#OverflowError"><code class="docutils literal notranslate">OverflowError</code></a></li> <li><a class="reference internal" href="#PythonFinalizationError"><code class="docutils literal notranslate">PythonFinalizationError</code></a></li> <li><a class="reference internal" href="#RecursionError"><code class="docutils literal notranslate">RecursionError</code></a></li> <li><a class="reference internal" href="#ReferenceError"><code class="docutils literal notranslate">ReferenceError</code></a></li> <li><a class="reference internal" href="#RuntimeError"><code class="docutils literal notranslate">RuntimeError</code></a></li> <li><a class="reference internal" href="#StopIteration"><code class="docutils literal notranslate">StopIteration</code></a><ul> <li><a class="reference internal" href="#StopIteration.value"><code class="docutils literal notranslate">value</code></a></li> </ul> </li> <li><a class="reference internal" href="#StopAsyncIteration"><code class="docutils literal notranslate">StopAsyncIteration</code></a></li> <li><a class="reference internal" href="#SyntaxError"><code class="docutils literal notranslate">SyntaxError</code></a><ul> <li><a class="reference internal" href="#SyntaxError.filename"><code class="docutils literal notranslate">filename</code></a></li> <li><a class="reference internal" href="#SyntaxError.lineno"><code class="docutils literal notranslate">lineno</code></a></li> <li><a class="reference internal" href="#SyntaxError.offset"><code class="docutils literal notranslate">offset</code></a></li> <li><a class="reference internal" href="#SyntaxError.text"><code class="docutils literal notranslate">text</code></a></li> <li><a class="reference internal" href="#SyntaxError.end_lineno"><code class="docutils literal notranslate">end_lineno</code></a></li> <li><a class="reference internal" href="#SyntaxError.end_offset"><code class="docutils literal notranslate">end_offset</code></a></li> </ul> </li> <li><a class="reference internal" href="#IndentationError"><code class="docutils literal notranslate">IndentationError</code></a></li> <li><a class="reference internal" href="#TabError"><code class="docutils literal notranslate">TabError</code></a></li> <li><a class="reference internal" href="#SystemError"><code class="docutils literal notranslate">SystemError</code></a></li> <li><a class="reference internal" href="#SystemExit"><code class="docutils literal notranslate">SystemExit</code></a><ul> <li><a class="reference internal" href="#SystemExit.code"><code class="docutils literal notranslate">code</code></a></li> </ul> </li> <li><a class="reference internal" href="#TypeError"><code class="docutils literal notranslate">TypeError</code></a></li> <li><a class="reference internal" href="#UnboundLocalError"><code class="docutils literal notranslate">UnboundLocalError</code></a></li> <li><a class="reference internal" href="#UnicodeError"><code class="docutils literal notranslate">UnicodeError</code></a><ul> <li><a class="reference internal" href="#UnicodeError.encoding"><code class="docutils literal notranslate">encoding</code></a></li> <li><a class="reference internal" href="#UnicodeError.reason"><code class="docutils literal notranslate">reason</code></a></li> <li><a class="reference internal" href="#UnicodeError.object"><code class="docutils literal notranslate">object</code></a></li> <li><a class="reference internal" href="#UnicodeError.start"><code class="docutils literal notranslate">start</code></a></li> <li><a class="reference internal" href="#UnicodeError.end"><code class="docutils literal notranslate">end</code></a></li> </ul> </li> <li><a class="reference internal" href="#UnicodeEncodeError"><code class="docutils literal notranslate">UnicodeEncodeError</code></a></li> <li><a class="reference internal" href="#UnicodeDecodeError"><code class="docutils literal notranslate">UnicodeDecodeError</code></a></li> <li><a class="reference internal" href="#UnicodeTranslateError"><code class="docutils literal notranslate">UnicodeTranslateError</code></a></li> <li><a class="reference internal" href="#ValueError"><code class="docutils literal notranslate">ValueError</code></a></li> <li><a class="reference internal" href="#ZeroDivisionError"><code class="docutils literal notranslate">ZeroDivisionError</code></a></li> <li><a class="reference internal" href="#EnvironmentError"><code class="docutils literal notranslate">EnvironmentError</code></a></li> <li><a class="reference internal" href="#IOError"><code class="docutils literal notranslate">IOError</code></a></li> <li><a class="reference internal" href="#WindowsError"><code class="docutils literal notranslate">WindowsError</code></a></li> <li><a class="reference internal" href="#os-exceptions">OS exceptions</a><ul> <li><a class="reference internal" href="#BlockingIOError"><code class="docutils literal notranslate">BlockingIOError</code></a><ul> <li><a class="reference internal" href="#BlockingIOError.characters_written"><code class="docutils literal notranslate">characters_written</code></a></li> </ul> </li> <li><a class="reference internal" href="#ChildProcessError"><code class="docutils literal notranslate">ChildProcessError</code></a></li> <li><a class="reference internal" href="#ConnectionError"><code class="docutils literal notranslate">ConnectionError</code></a></li> <li><a class="reference internal" href="#BrokenPipeError"><code class="docutils literal notranslate">BrokenPipeError</code></a></li> <li><a class="reference internal" href="#ConnectionAbortedError"><code class="docutils literal notranslate">ConnectionAbortedError</code></a></li> <li><a class="reference internal" href="#ConnectionRefusedError"><code class="docutils literal notranslate">ConnectionRefusedError</code></a></li> <li><a class="reference internal" href="#ConnectionResetError"><code class="docutils literal notranslate">ConnectionResetError</code></a></li> <li><a class="reference internal" href="#FileExistsError"><code class="docutils literal notranslate">FileExistsError</code></a></li> <li><a class="reference internal" href="#FileNotFoundError"><code class="docutils literal notranslate">FileNotFoundError</code></a></li> <li><a class="reference internal" href="#InterruptedError"><code class="docutils literal notranslate">InterruptedError</code></a></li> <li><a class="reference internal" href="#IsADirectoryError"><code class="docutils literal notranslate">IsADirectoryError</code></a></li> <li><a class="reference internal" href="#NotADirectoryError"><code class="docutils literal notranslate">NotADirectoryError</code></a></li> <li><a class="reference internal" href="#PermissionError"><code class="docutils literal notranslate">PermissionError</code></a></li> <li><a class="reference internal" href="#ProcessLookupError"><code class="docutils literal notranslate">ProcessLookupError</code></a></li> <li><a class="reference internal" href="#TimeoutError"><code class="docutils literal notranslate">TimeoutError</code></a></li> </ul> </li> </ul> </li> <li><a class="reference internal" href="#warnings">Warnings</a><ul> <li><a class="reference internal" href="#Warning"><code class="docutils literal notranslate">Warning</code></a></li> <li><a class="reference internal" href="#UserWarning"><code class="docutils literal notranslate">UserWarning</code></a></li> <li><a class="reference internal" href="#DeprecationWarning"><code class="docutils literal notranslate">DeprecationWarning</code></a></li> <li><a class="reference internal" href="#PendingDeprecationWarning"><code class="docutils literal notranslate">PendingDeprecationWarning</code></a></li> <li><a class="reference internal" href="#SyntaxWarning"><code class="docutils literal notranslate">SyntaxWarning</code></a></li> <li><a class="reference internal" href="#RuntimeWarning"><code class="docutils literal notranslate">RuntimeWarning</code></a></li> <li><a class="reference internal" href="#FutureWarning"><code class="docutils literal notranslate">FutureWarning</code></a></li> <li><a class="reference internal" href="#ImportWarning"><code class="docutils literal notranslate">ImportWarning</code></a></li> <li><a class="reference internal" href="#UnicodeWarning"><code class="docutils literal notranslate">UnicodeWarning</code></a></li> <li><a class="reference internal" href="#EncodingWarning"><code class="docutils literal notranslate">EncodingWarning</code></a></li> <li><a class="reference internal" href="#BytesWarning"><code class="docutils literal notranslate">BytesWarning</code></a></li> <li><a class="reference internal" href="#ResourceWarning"><code class="docutils literal notranslate">ResourceWarning</code></a></li> </ul> </li> <li><a class="reference internal" href="#exception-groups">Exception groups</a><ul> <li><a class="reference internal" href="#ExceptionGroup"><code class="docutils literal notranslate">ExceptionGroup</code></a></li> <li><a class="reference internal" href="#BaseExceptionGroup"><code class="docutils literal notranslate">BaseExceptionGroup</code></a><ul> <li><a class="reference internal" href="#BaseExceptionGroup.message"><code class="docutils literal notranslate">message</code></a></li> <li><a class="reference internal" href="#BaseExceptionGroup.exceptions"><code class="docutils literal notranslate">exceptions</code></a></li> <li><a class="reference internal" href="#BaseExceptionGroup.subgroup"><code class="docutils literal notranslate">subgroup()</code></a></li> <li><a class="reference internal" href="#BaseExceptionGroup.split"><code class="docutils literal notranslate">split()</code></a></li> <li><a class="reference internal" href="#BaseExceptionGroup.derive"><code class="docutils literal notranslate">derive()</code></a></li> </ul> </li> </ul> </li> <li><a class="reference internal" href="#exception-hierarchy">Exception hierarchy</a></li> </ul> </li> </ul> </div> <div> <h4>Previous topic</h4> <a href="stdtypes.html" 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selected>Auto</option> <option value="light">Light</option> <option value="dark">Dark</option> </select> </label> |</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <section id="built-in-exceptions"> <h1>Built-in Exceptions<a class="headerlink" href="#built-in-exceptions" title="Link to this heading">¶</a></h1> In Python, all exceptions must be instances of a class that derives from <a class="reference internal" href="#BaseException" title="BaseException"><code class="xref py py-class docutils literal notranslate">BaseException</code></a>. In a <a class="reference internal" href="../reference/compound_stmts.html#try"><code class="xref std std-keyword docutils literal notranslate">try</code></a> statement with an <a class="reference internal" href="../reference/compound_stmts.html#except"><code class="xref std std-keyword docutils literal notranslate">except</code></a> clause that mentions a particular class, that clause also handles any exception classes derived from that class (but not exception classes from which it is derived). Two exception classes that are not related via subclassing are never equivalent, even if they have the same name. The built-in exceptions listed in this chapter can be generated by the interpreter or built-in functions. Except where mentioned, they have an “associated value” indicating the detailed cause of the error. This may be a string or a tuple of several items of information (e.g., an error code and a string explaining the code). The associated value is usually passed as arguments to the exception class’s constructor. User code can raise built-in exceptions. This can be used to test an exception handler or to report an error condition “just like” the situation in which the interpreter raises the same exception; but beware that there is nothing to prevent user code from raising an inappropriate error. The built-in exception classes can be subclassed to define new exceptions; programmers are encouraged to derive new exceptions from the <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a> class or one of its subclasses, and not from <a class="reference internal" href="#BaseException" title="BaseException"><code class="xref py py-exc docutils literal notranslate">BaseException</code></a>. More information on defining exceptions is available in the Python Tutorial under <a class="reference internal" href="../tutorial/errors.html#tut-userexceptions">User-defined Exceptions</a>. <section id="exception-context"> <h2>Exception context<a class="headerlink" href="#exception-context" title="Link to this heading">¶</a></h2> Three attributes on exception objects provide information about the context in which the exception was raised: <dl class="py attribute"> <dt class="sig sig-object py" id="BaseException.__context__"> BaseException.__context__<a class="headerlink" href="#BaseException.__context__" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py" id="BaseException.__cause__"> BaseException.__cause__<a class="headerlink" href="#BaseException.__cause__" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py" id="BaseException.__suppress_context__"> BaseException.__suppress_context__<a class="headerlink" href="#BaseException.__suppress_context__" title="Link to this definition">¶</a></dt> <dd>When raising a new exception while another exception is already being handled, the new exception’s <code class="xref py py-attr docutils literal notranslate">__context__</code> attribute is automatically set to the handled exception. An exception may be handled when an <a class="reference internal" href="../reference/compound_stmts.html#except"><code class="xref std std-keyword docutils literal notranslate">except</code></a> or <a class="reference internal" href="../reference/compound_stmts.html#finally"><code class="xref std std-keyword docutils literal notranslate">finally</code></a> clause, or a <a class="reference internal" href="../reference/compound_stmts.html#with"><code class="xref std std-keyword docutils literal notranslate">with</code></a> statement, is used. This implicit exception context can be supplemented with an explicit cause by using <code class="xref std std-keyword docutils literal notranslate">from</code> with <a class="reference internal" href="../reference/simple_stmts.html#raise"><code class="xref std std-keyword docutils literal notranslate">raise</code></a>: <div class="highlight-python3 notranslate"><div class="highlight"><pre>raise new_exc from original_exc </pre></div> </div> The expression following <a class="reference internal" href="../reference/simple_stmts.html#raise"><code class="xref std std-keyword docutils literal notranslate">from</code></a> must be an exception or <code class="docutils literal notranslate">None</code>. It will be set as <code class="xref py py-attr docutils literal notranslate">__cause__</code> on the raised exception. Setting <code class="xref py py-attr docutils literal notranslate">__cause__</code> also implicitly sets the <code class="xref py py-attr docutils literal notranslate">__suppress_context__</code> attribute to <code class="docutils literal notranslate">True</code>, so that using <code class="docutils literal notranslate">raise new_exc from None</code> effectively replaces the old exception with the new one for display purposes (e.g. converting <a class="reference internal" href="#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate">KeyError</code></a> to <a class="reference internal" href="#AttributeError" title="AttributeError"><code class="xref py py-exc docutils literal notranslate">AttributeError</code></a>), while leaving the old exception available in <code class="xref py py-attr docutils literal notranslate">__context__</code> for introspection when debugging. The default traceback display code shows these chained exceptions in addition to the traceback for the exception itself. An explicitly chained exception in <code class="xref py py-attr docutils literal notranslate">__cause__</code> is always shown when present. An implicitly chained exception in <code class="xref py py-attr docutils literal notranslate">__context__</code> is shown only if <code class="xref py py-attr docutils literal notranslate">__cause__</code> is <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate">None</code></a> and <code class="xref py py-attr docutils literal notranslate">__suppress_context__</code> is false. In either case, the exception itself is always shown after any chained exceptions so that the final line of the traceback always shows the last exception that was raised. </dd></dl> </section> <section id="inheriting-from-built-in-exceptions"> <h2>Inheriting from built-in exceptions<a class="headerlink" href="#inheriting-from-built-in-exceptions" title="Link to this heading">¶</a></h2> User code can create subclasses that inherit from an exception type. It’s recommended to only subclass one exception type at a time to avoid any possible conflicts between how the bases handle the <code class="docutils literal notranslate">args</code> attribute, as well as due to possible memory layout incompatibilities. <div class="impl-detail compound"> CPython implementation detail: Most built-in exceptions are implemented in C for efficiency, see: <a class="extlink-source reference external" href="https://github.com/python/cpython/tree/3.13/Objects/exceptions.c">Objects/exceptions.c</a>. Some have custom memory layouts which makes it impossible to create a subclass that inherits from multiple exception types. The memory layout of a type is an implementation detail and might change between Python versions, leading to new conflicts in the future. Therefore, it’s recommended to avoid subclassing multiple exception types altogether. </div> </section> <section id="base-classes"> <h2>Base classes<a class="headerlink" href="#base-classes" title="Link to this heading">¶</a></h2> The following exceptions are used mostly as base classes for other exceptions. <dl class="py exception"> <dt class="sig sig-object py" id="BaseException"> exception BaseException<a class="headerlink" href="#BaseException" title="Link to this definition">¶</a></dt> <dd>The base class for all built-in exceptions. It is not meant to be directly inherited by user-defined classes (for that, use <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a>). If <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-func docutils literal notranslate">str()</code></a> is called on an instance of this class, the representation of the argument(s) to the instance are returned, or the empty string when there were no arguments. <dl class="py attribute"> <dt class="sig sig-object py" id="BaseException.args"> args<a class="headerlink" href="#BaseException.args" title="Link to this definition">¶</a></dt> <dd>The tuple of arguments given to the exception constructor. Some built-in exceptions (like <a class="reference internal" href="#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate">OSError</code></a>) expect a certain number of arguments and assign a special meaning to the elements of this tuple, while others are usually called only with a single string giving an error message. </dd></dl> <dl class="py method"> <dt class="sig sig-object py" id="BaseException.with_traceback"> with_traceback(tb)<a class="headerlink" href="#BaseException.with_traceback" title="Link to this definition">¶</a></dt> <dd>This method sets tb as the new traceback for the exception and returns the exception object. It was more commonly used before the exception chaining features of <a class="pep reference external" href="https://peps.python.org/pep-3134/">PEP 3134</a> became available. The following example shows how we can convert an instance of <code class="docutils literal notranslate">SomeException</code> into an instance of <code class="docutils literal notranslate">OtherException</code> while preserving the traceback. Once raised, the current frame is pushed onto the traceback of the <code class="docutils literal notranslate">OtherException</code>, as would have happened to the traceback of the original <code class="docutils literal notranslate">SomeException</code> had we allowed it to propagate to the caller. <div class="highlight-python3 notranslate"><div class="highlight"><pre>try: ... except SomeException: tb = sys.exception().__traceback__ raise OtherException(...).with_traceback(tb) </pre></div> </div> </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="BaseException.__traceback__"> __traceback__<a class="headerlink" href="#BaseException.__traceback__" title="Link to this definition">¶</a></dt> <dd>A writable field that holds the <a class="reference internal" href="../reference/datamodel.html#traceback-objects">traceback object</a> associated with this exception. See also: <a class="reference internal" href="../reference/simple_stmts.html#raise">The raise statement</a>. </dd></dl> <dl class="py method"> <dt class="sig sig-object py" id="BaseException.add_note"> add_note(note)<a class="headerlink" href="#BaseException.add_note" title="Link to this definition">¶</a></dt> <dd>Add the string <code class="docutils literal notranslate">note</code> to the exception’s notes which appear in the standard traceback after the exception string. A <a class="reference internal" href="#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> is raised if <code class="docutils literal notranslate">note</code> is not a string. <div class="versionadded"> Added in version 3.11. </div> </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="BaseException.__notes__"> __notes__<a class="headerlink" href="#BaseException.__notes__" title="Link to this definition">¶</a></dt> <dd>A list of the notes of this exception, which were added with <a class="reference internal" href="#BaseException.add_note" title="BaseException.add_note"><code class="xref py py-meth docutils literal notranslate">add_note()</code></a>. This attribute is created when <a class="reference internal" href="#BaseException.add_note" title="BaseException.add_note"><code class="xref py py-meth docutils literal notranslate">add_note()</code></a> is called. <div class="versionadded"> Added in version 3.11. </div> </dd></dl> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="Exception"> exception Exception<a class="headerlink" href="#Exception" title="Link to this definition">¶</a></dt> <dd>All built-in, non-system-exiting exceptions are derived from this class. All user-defined exceptions should also be derived from this class. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ArithmeticError"> exception ArithmeticError<a class="headerlink" href="#ArithmeticError" title="Link to this definition">¶</a></dt> <dd>The base class for those built-in exceptions that are raised for various arithmetic errors: <a class="reference internal" href="#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal notranslate">OverflowError</code></a>, <a class="reference internal" href="#ZeroDivisionError" title="ZeroDivisionError"><code class="xref py py-exc docutils literal notranslate">ZeroDivisionError</code></a>, <a class="reference internal" href="#FloatingPointError" title="FloatingPointError"><code class="xref py py-exc docutils literal notranslate">FloatingPointError</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="BufferError"> exception BufferError<a class="headerlink" href="#BufferError" title="Link to this definition">¶</a></dt> <dd>Raised when a <a class="reference internal" href="../c-api/buffer.html#bufferobjects">buffer</a> related operation cannot be performed. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="LookupError"> exception LookupError<a class="headerlink" href="#LookupError" title="Link to this definition">¶</a></dt> <dd>The base class for the exceptions that are raised when a key or index used on a mapping or sequence is invalid: <a class="reference internal" href="#IndexError" title="IndexError"><code class="xref py py-exc docutils literal notranslate">IndexError</code></a>, <a class="reference internal" href="#KeyError" title="KeyError"><code class="xref py py-exc docutils literal notranslate">KeyError</code></a>. This can be raised directly by <a class="reference internal" href="codecs.html#codecs.lookup" title="codecs.lookup"><code class="xref py py-func docutils literal notranslate">codecs.lookup()</code></a>. </dd></dl> </section> <section id="concrete-exceptions"> <h2>Concrete exceptions<a class="headerlink" href="#concrete-exceptions" title="Link to this heading">¶</a></h2> The following exceptions are the exceptions that are usually raised. <dl class="py exception"> <dt class="sig sig-object py" id="AssertionError"> exception AssertionError<a class="headerlink" href="#AssertionError" title="Link to this definition">¶</a></dt> <dd>Raised when an <a class="reference internal" href="../reference/simple_stmts.html#assert"><code class="xref std std-keyword docutils literal notranslate">assert</code></a> statement fails. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="AttributeError"> exception AttributeError<a class="headerlink" href="#AttributeError" title="Link to this definition">¶</a></dt> <dd>Raised when an attribute reference (see <a class="reference internal" href="../reference/expressions.html#attribute-references">Attribute references</a>) or assignment fails. (When an object does not support attribute references or attribute assignments at all, <a class="reference internal" href="#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> is raised.) The <code class="xref py py-attr docutils literal notranslate">name</code> and <code class="xref py py-attr docutils literal notranslate">obj</code> attributes can be set using keyword-only arguments to the constructor. When set they represent the name of the attribute that was attempted to be accessed and the object that was accessed for said attribute, respectively. <div class="versionchanged"> Changed in version 3.10: Added the <code class="xref py py-attr docutils literal notranslate">name</code> and <code class="xref py py-attr docutils literal notranslate">obj</code> attributes. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="EOFError"> exception EOFError<a class="headerlink" href="#EOFError" title="Link to this definition">¶</a></dt> <dd>Raised when the <a class="reference internal" href="functions.html#input" title="input"><code class="xref py py-func docutils literal notranslate">input()</code></a> function hits an end-of-file condition (EOF) without reading any data. (N.B.: the <code class="xref py py-meth docutils literal notranslate">io.IOBase.read()</code> and <a class="reference internal" href="io.html#io.IOBase.readline" title="io.IOBase.readline"><code class="xref py py-meth docutils literal notranslate">io.IOBase.readline()</code></a> methods return an empty string when they hit EOF.) </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="FloatingPointError"> exception FloatingPointError<a class="headerlink" href="#FloatingPointError" title="Link to this definition">¶</a></dt> <dd>Not currently used. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="GeneratorExit"> exception GeneratorExit<a class="headerlink" href="#GeneratorExit" title="Link to this definition">¶</a></dt> <dd>Raised when a <a class="reference internal" href="../glossary.html#term-generator">generator</a> or <a class="reference internal" href="../glossary.html#term-coroutine">coroutine</a> is closed; see <a class="reference internal" href="../reference/expressions.html#generator.close" title="generator.close"><code class="xref py py-meth docutils literal notranslate">generator.close()</code></a> and <a class="reference internal" href="../reference/datamodel.html#coroutine.close" title="coroutine.close"><code class="xref py py-meth docutils literal notranslate">coroutine.close()</code></a>. It directly inherits from <a class="reference internal" href="#BaseException" title="BaseException"><code class="xref py py-exc docutils literal notranslate">BaseException</code></a> instead of <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a> since it is technically not an error. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ImportError"> exception ImportError<a class="headerlink" href="#ImportError" title="Link to this definition">¶</a></dt> <dd>Raised when the <a class="reference internal" href="../reference/simple_stmts.html#import"><code class="xref std std-keyword docutils literal notranslate">import</code></a> statement has troubles trying to load a module. Also raised when the “from list” in <code class="docutils literal notranslate">from ... import</code> has a name that cannot be found. The optional name and path keyword-only arguments set the corresponding attributes: <dl class="py attribute"> <dt class="sig sig-object py" id="ImportError.name"> name<a class="headerlink" href="#ImportError.name" title="Link to this definition">¶</a></dt> <dd>The name of the module that was attempted to be imported. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="ImportError.path"> path<a class="headerlink" href="#ImportError.path" title="Link to this definition">¶</a></dt> <dd>The path to any file which triggered the exception. </dd></dl> <div class="versionchanged"> Changed in version 3.3: Added the <a class="reference internal" href="#ImportError.name" title="ImportError.name"><code class="xref py py-attr docutils literal notranslate">name</code></a> and <a class="reference internal" href="#ImportError.path" title="ImportError.path"><code class="xref py py-attr docutils literal notranslate">path</code></a> attributes. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ModuleNotFoundError"> exception ModuleNotFoundError<a class="headerlink" href="#ModuleNotFoundError" title="Link to this definition">¶</a></dt> <dd>A subclass of <a class="reference internal" href="#ImportError" title="ImportError"><code class="xref py py-exc docutils literal notranslate">ImportError</code></a> which is raised by <a class="reference internal" href="../reference/simple_stmts.html#import"><code class="xref std std-keyword docutils literal notranslate">import</code></a> when a module could not be located. It is also raised when <code class="docutils literal notranslate">None</code> is found in <a class="reference internal" href="sys.html#sys.modules" title="sys.modules"><code class="xref py py-data docutils literal notranslate">sys.modules</code></a>. <div class="versionadded"> Added in version 3.6. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="IndexError"> exception IndexError<a class="headerlink" href="#IndexError" title="Link to this definition">¶</a></dt> <dd>Raised when a sequence subscript is out of range. (Slice indices are silently truncated to fall in the allowed range; if an index is not an integer, <a class="reference internal" href="#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> is raised.) </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="KeyError"> exception KeyError<a class="headerlink" href="#KeyError" title="Link to this definition">¶</a></dt> <dd>Raised when a mapping (dictionary) key is not found in the set of existing keys. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="KeyboardInterrupt"> exception KeyboardInterrupt<a class="headerlink" href="#KeyboardInterrupt" title="Link to this definition">¶</a></dt> <dd>Raised when the user hits the interrupt key (normally <kbd class="kbd compound docutils literal notranslate"><kbd class="kbd docutils literal notranslate">Control</kbd>-<kbd class="kbd docutils literal notranslate">C</kbd></kbd> or <kbd class="kbd docutils literal notranslate">Delete</kbd>). During execution, a check for interrupts is made regularly. The exception inherits from <a class="reference internal" href="#BaseException" title="BaseException"><code class="xref py py-exc docutils literal notranslate">BaseException</code></a> so as to not be accidentally caught by code that catches <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a> and thus prevent the interpreter from exiting. <div class="admonition note"> Note Catching a <a class="reference internal" href="#KeyboardInterrupt" title="KeyboardInterrupt"><code class="xref py py-exc docutils literal notranslate">KeyboardInterrupt</code></a> requires special consideration. Because it can be raised at unpredictable points, it may, in some circumstances, leave the running program in an inconsistent state. It is generally best to allow <a class="reference internal" href="#KeyboardInterrupt" title="KeyboardInterrupt"><code class="xref py py-exc docutils literal notranslate">KeyboardInterrupt</code></a> to end the program as quickly as possible or avoid raising it entirely. (See <a class="reference internal" href="signal.html#handlers-and-exceptions">Note on Signal Handlers and Exceptions</a>.) </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="MemoryError"> exception MemoryError<a class="headerlink" href="#MemoryError" title="Link to this definition">¶</a></dt> <dd>Raised when an operation runs out of memory but the situation may still be rescued (by deleting some objects). The associated value is a string indicating what kind of (internal) operation ran out of memory. Note that because of the underlying memory management architecture (C’s <code class="xref c c-func docutils literal notranslate">malloc()</code> function), the interpreter may not always be able to completely recover from this situation; it nevertheless raises an exception so that a stack traceback can be printed, in case a run-away program was the cause. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="NameError"> exception NameError<a class="headerlink" href="#NameError" title="Link to this definition">¶</a></dt> <dd>Raised when a local or global name is not found. This applies only to unqualified names. The associated value is an error message that includes the name that could not be found. The <code class="xref py py-attr docutils literal notranslate">name</code> attribute can be set using a keyword-only argument to the constructor. When set it represent the name of the variable that was attempted to be accessed. <div class="versionchanged"> Changed in version 3.10: Added the <code class="xref py py-attr docutils literal notranslate">name</code> attribute. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="NotImplementedError"> exception NotImplementedError<a class="headerlink" href="#NotImplementedError" title="Link to this definition">¶</a></dt> <dd>This exception is derived from <a class="reference internal" href="#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate">RuntimeError</code></a>. In user defined base classes, abstract methods should raise this exception when they require derived classes to override the method, or while the class is being developed to indicate that the real implementation still needs to be added. <div class="admonition note"> Note It should not be used to indicate that an operator or method is not meant to be supported at all – in that case either leave the operator / method undefined or, if a subclass, set it to <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-data docutils literal notranslate">None</code></a>. </div> <div class="admonition note"> Note <code class="docutils literal notranslate">NotImplementedError</code> and <a class="reference internal" href="constants.html#NotImplemented" title="NotImplemented"><code class="xref py py-data docutils literal notranslate">NotImplemented</code></a> are not interchangeable, even though they have similar names and purposes. See <code class="xref py py-data docutils literal notranslate">NotImplemented</code> for details on when to use it. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="OSError"> exception OSError([arg])<a class="headerlink" href="#OSError" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py"> exception OSError(errno, strerror[, filename[, winerror[, filename2]]])</dt> <dd>This exception is raised when a system function returns a system-related error, including I/O failures such as “file not found” or “disk full” (not for illegal argument types or other incidental errors). The second form of the constructor sets the corresponding attributes, described below. The attributes default to <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate">None</code></a> if not specified. For backwards compatibility, if three arguments are passed, the <a class="reference internal" href="#BaseException.args" title="BaseException.args"><code class="xref py py-attr docutils literal notranslate">args</code></a> attribute contains only a 2-tuple of the first two constructor arguments. The constructor often actually returns a subclass of <a class="reference internal" href="#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate">OSError</code></a>, as described in <a class="reference internal" href="#os-exceptions">OS exceptions</a> below. The particular subclass depends on the final <a class="reference internal" href="#OSError.errno" title="OSError.errno"><code class="xref py py-attr docutils literal notranslate">errno</code></a> value. This behaviour only occurs when constructing <a class="reference internal" href="#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate">OSError</code></a> directly or via an alias, and is not inherited when subclassing. <dl class="py attribute"> <dt class="sig sig-object py" id="OSError.errno"> errno<a class="headerlink" href="#OSError.errno" title="Link to this definition">¶</a></dt> <dd>A numeric error code from the C variable <code class="xref c c-data docutils literal notranslate">errno</code>. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="OSError.winerror"> winerror<a class="headerlink" href="#OSError.winerror" title="Link to this definition">¶</a></dt> <dd>Under Windows, this gives you the native Windows error code. The <a class="reference internal" href="#OSError.errno" title="OSError.errno"><code class="xref py py-attr docutils literal notranslate">errno</code></a> attribute is then an approximate translation, in POSIX terms, of that native error code. Under Windows, if the winerror constructor argument is an integer, the <a class="reference internal" href="#OSError.errno" title="OSError.errno"><code class="xref py py-attr docutils literal notranslate">errno</code></a> attribute is determined from the Windows error code, and the errno argument is ignored. On other platforms, the winerror argument is ignored, and the <a class="reference internal" href="#OSError.winerror" title="OSError.winerror"><code class="xref py py-attr docutils literal notranslate">winerror</code></a> attribute does not exist. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="OSError.strerror"> strerror<a class="headerlink" href="#OSError.strerror" title="Link to this definition">¶</a></dt> <dd>The corresponding error message, as provided by the operating system. It is formatted by the C functions <code class="xref c c-func docutils literal notranslate">perror()</code> under POSIX, and <code class="xref c c-func docutils literal notranslate">FormatMessage()</code> under Windows. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="OSError.filename"> filename<a class="headerlink" href="#OSError.filename" title="Link to this definition">¶</a></dt> <dt class="sig sig-object py" id="OSError.filename2"> filename2<a class="headerlink" href="#OSError.filename2" title="Link to this definition">¶</a></dt> <dd>For exceptions that involve a file system path (such as <a class="reference internal" href="functions.html#open" title="open"><code class="xref py py-func docutils literal notranslate">open()</code></a> or <a class="reference internal" href="os.html#os.unlink" title="os.unlink"><code class="xref py py-func docutils literal notranslate">os.unlink()</code></a>), <a class="reference internal" href="#OSError.filename" title="OSError.filename"><code class="xref py py-attr docutils literal notranslate">filename</code></a> is the file name passed to the function. For functions that involve two file system paths (such as <a class="reference internal" href="os.html#os.rename" title="os.rename"><code class="xref py py-func docutils literal notranslate">os.rename()</code></a>), <a class="reference internal" href="#OSError.filename2" title="OSError.filename2"><code class="xref py py-attr docutils literal notranslate">filename2</code></a> corresponds to the second file name passed to the function. </dd></dl> <div class="versionchanged"> Changed in version 3.3: <a class="reference internal" href="#EnvironmentError" title="EnvironmentError"><code class="xref py py-exc docutils literal notranslate">EnvironmentError</code></a>, <a class="reference internal" href="#IOError" title="IOError"><code class="xref py py-exc docutils literal notranslate">IOError</code></a>, <a class="reference internal" href="#WindowsError" title="WindowsError"><code class="xref py py-exc docutils literal notranslate">WindowsError</code></a>, <a class="reference internal" href="socket.html#socket.error" title="socket.error"><code class="xref py py-exc docutils literal notranslate">socket.error</code></a>, <a class="reference internal" href="select.html#select.error" title="select.error"><code class="xref py py-exc docutils literal notranslate">select.error</code></a> and <code class="xref py py-exc docutils literal notranslate">mmap.error</code> have been merged into <a class="reference internal" href="#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate">OSError</code></a>, and the constructor may return a subclass. </div> <div class="versionchanged"> Changed in version 3.4: The <a class="reference internal" href="#OSError.filename" title="OSError.filename"><code class="xref py py-attr docutils literal notranslate">filename</code></a> attribute is now the original file name passed to the function, instead of the name encoded to or decoded from the <a class="reference internal" href="../glossary.html#term-filesystem-encoding-and-error-handler">filesystem encoding and error handler</a>. Also, the filename2 constructor argument and attribute was added. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="OverflowError"> exception OverflowError<a class="headerlink" href="#OverflowError" title="Link to this definition">¶</a></dt> <dd>Raised when the result of an arithmetic operation is too large to be represented. This cannot occur for integers (which would rather raise <a class="reference internal" href="#MemoryError" title="MemoryError"><code class="xref py py-exc docutils literal notranslate">MemoryError</code></a> than give up). However, for historical reasons, OverflowError is sometimes raised for integers that are outside a required range. Because of the lack of standardization of floating-point exception handling in C, most floating-point operations are not checked. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="PythonFinalizationError"> exception PythonFinalizationError<a class="headerlink" href="#PythonFinalizationError" title="Link to this definition">¶</a></dt> <dd>This exception is derived from <a class="reference internal" href="#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate">RuntimeError</code></a>. It is raised when an operation is blocked during interpreter shutdown also known as <a class="reference internal" href="../glossary.html#term-interpreter-shutdown">Python finalization</a>. Examples of operations which can be blocked with a <a class="reference internal" href="#PythonFinalizationError" title="PythonFinalizationError"><code class="xref py py-exc docutils literal notranslate">PythonFinalizationError</code></a> during the Python finalization: <ul class="simple"> <li>Creating a new Python thread.</li> <li><a class="reference internal" href="os.html#os.fork" title="os.fork"><code class="xref py py-func docutils literal notranslate">os.fork()</code></a>.</li> </ul> See also the <a class="reference internal" href="sys.html#sys.is_finalizing" title="sys.is_finalizing"><code class="xref py py-func docutils literal notranslate">sys.is_finalizing()</code></a> function. <div class="versionadded"> Added in version 3.13: Previously, a plain <a class="reference internal" href="#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate">RuntimeError</code></a> was raised. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="RecursionError"> exception RecursionError<a class="headerlink" href="#RecursionError" title="Link to this definition">¶</a></dt> <dd>This exception is derived from <a class="reference internal" href="#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate">RuntimeError</code></a>. It is raised when the interpreter detects that the maximum recursion depth (see <a class="reference internal" href="sys.html#sys.getrecursionlimit" title="sys.getrecursionlimit"><code class="xref py py-func docutils literal notranslate">sys.getrecursionlimit()</code></a>) is exceeded. <div class="versionadded"> Added in version 3.5: Previously, a plain <a class="reference internal" href="#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate">RuntimeError</code></a> was raised. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ReferenceError"> exception ReferenceError<a class="headerlink" href="#ReferenceError" title="Link to this definition">¶</a></dt> <dd>This exception is raised when a weak reference proxy, created by the <a class="reference internal" href="weakref.html#weakref.proxy" title="weakref.proxy"><code class="xref py py-func docutils literal notranslate">weakref.proxy()</code></a> function, is used to access an attribute of the referent after it has been garbage collected. For more information on weak references, see the <a class="reference internal" href="weakref.html#module-weakref" title="weakref: Support for weak references and weak dictionaries."><code class="xref py py-mod docutils literal notranslate">weakref</code></a> module. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="RuntimeError"> exception RuntimeError<a class="headerlink" href="#RuntimeError" title="Link to this definition">¶</a></dt> <dd>Raised when an error is detected that doesn’t fall in any of the other categories. The associated value is a string indicating what precisely went wrong. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="StopIteration"> exception StopIteration<a class="headerlink" href="#StopIteration" title="Link to this definition">¶</a></dt> <dd>Raised by built-in function <a class="reference internal" href="functions.html#next" title="next"><code class="xref py py-func docutils literal notranslate">next()</code></a> and an <a class="reference internal" href="../glossary.html#term-iterator">iterator</a>'s <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 to signal that there are no further items produced by the iterator. <dl class="py attribute"> <dt class="sig sig-object py" id="StopIteration.value"> value<a class="headerlink" href="#StopIteration.value" title="Link to this definition">¶</a></dt> <dd>The exception object has a single attribute <code class="xref py py-attr docutils literal notranslate">value</code>, which is given as an argument when constructing the exception, and defaults to <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate">None</code></a>. </dd></dl> When a <a class="reference internal" href="../glossary.html#term-generator">generator</a> or <a class="reference internal" href="../glossary.html#term-coroutine">coroutine</a> function returns, a new <a class="reference internal" href="#StopIteration" title="StopIteration"><code class="xref py py-exc docutils literal notranslate">StopIteration</code></a> instance is raised, and the value returned by the function is used as the <a class="reference internal" href="#StopIteration.value" title="StopIteration.value"><code class="xref py py-attr docutils literal notranslate">value</code></a> parameter to the constructor of the exception. If a generator code directly or indirectly raises <a class="reference internal" href="#StopIteration" title="StopIteration"><code class="xref py py-exc docutils literal notranslate">StopIteration</code></a>, it is converted into a <a class="reference internal" href="#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate">RuntimeError</code></a> (retaining the <a class="reference internal" href="#StopIteration" title="StopIteration"><code class="xref py py-exc docutils literal notranslate">StopIteration</code></a> as the new exception’s cause). <div class="versionchanged"> Changed in version 3.3: Added <code class="docutils literal notranslate">value</code> attribute and the ability for generator functions to use it to return a value. </div> <div class="versionchanged"> Changed in version 3.5: Introduced the RuntimeError transformation via <code class="docutils literal notranslate">from __future__ import generator_stop</code>, see <a class="pep reference external" href="https://peps.python.org/pep-0479/">PEP 479</a>. </div> <div class="versionchanged"> Changed in version 3.7: Enable <a class="pep reference external" href="https://peps.python.org/pep-0479/">PEP 479</a> for all code by default: a <a class="reference internal" href="#StopIteration" title="StopIteration"><code class="xref py py-exc docutils literal notranslate">StopIteration</code></a> error raised in a generator is transformed into a <a class="reference internal" href="#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate">RuntimeError</code></a>. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="StopAsyncIteration"> exception StopAsyncIteration<a class="headerlink" href="#StopAsyncIteration" title="Link to this definition">¶</a></dt> <dd>Must be raised by <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 an <a class="reference internal" href="../glossary.html#term-asynchronous-iterator">asynchronous iterator</a> object to stop the iteration. <div class="versionadded"> Added in version 3.5. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="SyntaxError"> exception SyntaxError(message, details)<a class="headerlink" href="#SyntaxError" title="Link to this definition">¶</a></dt> <dd>Raised when the parser encounters a syntax error. This may occur in an <a class="reference internal" href="../reference/simple_stmts.html#import"><code class="xref std std-keyword docutils literal notranslate">import</code></a> statement, in a call to the built-in functions <a class="reference internal" href="functions.html#compile" title="compile"><code class="xref py py-func docutils literal notranslate">compile()</code></a>, <a class="reference internal" href="functions.html#exec" title="exec"><code class="xref py py-func docutils literal notranslate">exec()</code></a>, or <a class="reference internal" href="functions.html#eval" title="eval"><code class="xref py py-func docutils literal notranslate">eval()</code></a>, or when reading the initial script or standard input (also interactively). The <a class="reference internal" href="stdtypes.html#str" title="str"><code class="xref py py-func docutils literal notranslate">str()</code></a> of the exception instance returns only the error message. Details is a tuple whose members are also available as separate attributes. <dl class="py attribute"> <dt class="sig sig-object py" id="SyntaxError.filename"> filename<a class="headerlink" href="#SyntaxError.filename" title="Link to this definition">¶</a></dt> <dd>The name of the file the syntax error occurred in. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="SyntaxError.lineno"> lineno<a class="headerlink" href="#SyntaxError.lineno" title="Link to this definition">¶</a></dt> <dd>Which line number in the file the error occurred in. This is 1-indexed: the first line in the file has a <code class="docutils literal notranslate">lineno</code> of 1. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="SyntaxError.offset"> offset<a class="headerlink" href="#SyntaxError.offset" title="Link to this definition">¶</a></dt> <dd>The column in the line where the error occurred. This is 1-indexed: the first character in the line has an <code class="docutils literal notranslate">offset</code> of 1. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="SyntaxError.text"> text<a class="headerlink" href="#SyntaxError.text" title="Link to this definition">¶</a></dt> <dd>The source code text involved in the error. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="SyntaxError.end_lineno"> end_lineno<a class="headerlink" href="#SyntaxError.end_lineno" title="Link to this definition">¶</a></dt> <dd>Which line number in the file the error occurred ends in. This is 1-indexed: the first line in the file has a <code class="docutils literal notranslate">lineno</code> of 1. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="SyntaxError.end_offset"> end_offset<a class="headerlink" href="#SyntaxError.end_offset" title="Link to this definition">¶</a></dt> <dd>The column in the end line where the error occurred finishes. This is 1-indexed: the first character in the line has an <code class="docutils literal notranslate">offset</code> of 1. </dd></dl> For errors in f-string fields, the message is prefixed by “f-string: ” and the offsets are offsets in a text constructed from the replacement expression. For example, compiling f’Bad {a b} field’ results in this args attribute: (‘f-string: …’, (‘’, 1, 2, ‘(a b)n’, 1, 5)). <div class="versionchanged"> Changed in version 3.10: Added the <a class="reference internal" href="#SyntaxError.end_lineno" title="SyntaxError.end_lineno"><code class="xref py py-attr docutils literal notranslate">end_lineno</code></a> and <a class="reference internal" href="#SyntaxError.end_offset" title="SyntaxError.end_offset"><code class="xref py py-attr docutils literal notranslate">end_offset</code></a> attributes. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="IndentationError"> exception IndentationError<a class="headerlink" href="#IndentationError" title="Link to this definition">¶</a></dt> <dd>Base class for syntax errors related to incorrect indentation. This is a subclass of <a class="reference internal" href="#SyntaxError" title="SyntaxError"><code class="xref py py-exc docutils literal notranslate">SyntaxError</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="TabError"> exception TabError<a class="headerlink" href="#TabError" title="Link to this definition">¶</a></dt> <dd>Raised when indentation contains an inconsistent use of tabs and spaces. This is a subclass of <a class="reference internal" href="#IndentationError" title="IndentationError"><code class="xref py py-exc docutils literal notranslate">IndentationError</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="SystemError"> exception SystemError<a class="headerlink" href="#SystemError" title="Link to this definition">¶</a></dt> <dd>Raised when the interpreter finds an internal error, but the situation does not look so serious to cause it to abandon all hope. The associated value is a string indicating what went wrong (in low-level terms). You should report this to the author or maintainer of your Python interpreter. Be sure to report the version of the Python interpreter (<code class="docutils literal notranslate">sys.version</code>; it is also printed at the start of an interactive Python session), the exact error message (the exception’s associated value) and if possible the source of the program that triggered the error. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="SystemExit"> exception SystemExit<a class="headerlink" href="#SystemExit" title="Link to this definition">¶</a></dt> <dd>This exception is raised by the <a class="reference internal" href="sys.html#sys.exit" title="sys.exit"><code class="xref py py-func docutils literal notranslate">sys.exit()</code></a> function. It inherits from <a class="reference internal" href="#BaseException" title="BaseException"><code class="xref py py-exc docutils literal notranslate">BaseException</code></a> instead of <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a> so that it is not accidentally caught by code that catches <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a>. This allows the exception to properly propagate up and cause the interpreter to exit. When it is not handled, the Python interpreter exits; no stack traceback is printed. The constructor accepts the same optional argument passed to <a class="reference internal" href="sys.html#sys.exit" title="sys.exit"><code class="xref py py-func docutils literal notranslate">sys.exit()</code></a>. If the value is an integer, it specifies the system exit status (passed to C’s <code class="xref c c-func docutils literal notranslate">exit()</code> function); if it is <code class="docutils literal notranslate">None</code>, the exit status is zero; if it has another type (such as a string), the object’s value is printed and the exit status is one. A call to <a class="reference internal" href="sys.html#sys.exit" title="sys.exit"><code class="xref py py-func docutils literal notranslate">sys.exit()</code></a> is translated into an exception so that clean-up handlers (<a class="reference internal" href="../reference/compound_stmts.html#finally"><code class="xref std std-keyword docutils literal notranslate">finally</code></a> clauses of <a class="reference internal" href="../reference/compound_stmts.html#try"><code class="xref std std-keyword docutils literal notranslate">try</code></a> statements) can be executed, and so that a debugger can execute a script without running the risk of losing control. The <a class="reference internal" href="os.html#os._exit" title="os._exit"><code class="xref py py-func docutils literal notranslate">os._exit()</code></a> function can be used if it is absolutely positively necessary to exit immediately (for example, in the child process after a call to <a class="reference internal" href="os.html#os.fork" title="os.fork"><code class="xref py py-func docutils literal notranslate">os.fork()</code></a>). <dl class="py attribute"> <dt class="sig sig-object py" id="SystemExit.code"> code<a class="headerlink" href="#SystemExit.code" title="Link to this definition">¶</a></dt> <dd>The exit status or error message that is passed to the constructor. (Defaults to <code class="docutils literal notranslate">None</code>.) </dd></dl> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="TypeError"> exception TypeError<a class="headerlink" href="#TypeError" title="Link to this definition">¶</a></dt> <dd>Raised when an operation or function is applied to an object of inappropriate type. The associated value is a string giving details about the type mismatch. This exception may be raised by user code to indicate that an attempted operation on an object is not supported, and is not meant to be. If an object is meant to support a given operation but has not yet provided an implementation, <a class="reference internal" href="#NotImplementedError" title="NotImplementedError"><code class="xref py py-exc docutils literal notranslate">NotImplementedError</code></a> is the proper exception to raise. Passing arguments of the wrong type (e.g. passing a <a class="reference internal" href="stdtypes.html#list" title="list"><code class="xref py py-class docutils literal notranslate">list</code></a> when an <a class="reference internal" href="functions.html#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a> is expected) should result in a <a class="reference internal" href="#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a>, but passing arguments with the wrong value (e.g. a number outside expected boundaries) should result in a <a class="reference internal" href="#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate">ValueError</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="UnboundLocalError"> exception UnboundLocalError<a class="headerlink" href="#UnboundLocalError" title="Link to this definition">¶</a></dt> <dd>Raised when a reference is made to a local variable in a function or method, but no value has been bound to that variable. This is a subclass of <a class="reference internal" href="#NameError" title="NameError"><code class="xref py py-exc docutils literal notranslate">NameError</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="UnicodeError"> exception UnicodeError<a class="headerlink" href="#UnicodeError" title="Link to this definition">¶</a></dt> <dd>Raised when a Unicode-related encoding or decoding error occurs. It is a subclass of <a class="reference internal" href="#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate">ValueError</code></a>. <a class="reference internal" href="#UnicodeError" title="UnicodeError"><code class="xref py py-exc docutils literal notranslate">UnicodeError</code></a> has attributes that describe the encoding or decoding error. For example, <code class="docutils literal notranslate">err.object[err.start:err.end]</code> gives the particular invalid input that the codec failed on. <dl class="py attribute"> <dt class="sig sig-object py" id="UnicodeError.encoding"> encoding<a class="headerlink" href="#UnicodeError.encoding" title="Link to this definition">¶</a></dt> <dd>The name of the encoding that raised the error. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="UnicodeError.reason"> reason<a class="headerlink" href="#UnicodeError.reason" title="Link to this definition">¶</a></dt> <dd>A string describing the specific codec error. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="UnicodeError.object"> object<a class="headerlink" href="#UnicodeError.object" title="Link to this definition">¶</a></dt> <dd>The object the codec was attempting to encode or decode. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="UnicodeError.start"> start<a class="headerlink" href="#UnicodeError.start" title="Link to this definition">¶</a></dt> <dd>The first index of invalid data in <a class="reference internal" href="functions.html#object" title="object"><code class="xref py py-attr docutils literal notranslate">object</code></a>. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="UnicodeError.end"> end<a class="headerlink" href="#UnicodeError.end" title="Link to this definition">¶</a></dt> <dd>The index after the last invalid data in <a class="reference internal" href="functions.html#object" title="object"><code class="xref py py-attr docutils literal notranslate">object</code></a>. </dd></dl> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="UnicodeEncodeError"> exception UnicodeEncodeError<a class="headerlink" href="#UnicodeEncodeError" title="Link to this definition">¶</a></dt> <dd>Raised when a Unicode-related error occurs during encoding. It is a subclass of <a class="reference internal" href="#UnicodeError" title="UnicodeError"><code class="xref py py-exc docutils literal notranslate">UnicodeError</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="UnicodeDecodeError"> exception UnicodeDecodeError<a class="headerlink" href="#UnicodeDecodeError" title="Link to this definition">¶</a></dt> <dd>Raised when a Unicode-related error occurs during decoding. It is a subclass of <a class="reference internal" href="#UnicodeError" title="UnicodeError"><code class="xref py py-exc docutils literal notranslate">UnicodeError</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="UnicodeTranslateError"> exception UnicodeTranslateError<a class="headerlink" href="#UnicodeTranslateError" title="Link to this definition">¶</a></dt> <dd>Raised when a Unicode-related error occurs during translating. It is a subclass of <a class="reference internal" href="#UnicodeError" title="UnicodeError"><code class="xref py py-exc docutils literal notranslate">UnicodeError</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ValueError"> exception ValueError<a class="headerlink" href="#ValueError" title="Link to this definition">¶</a></dt> <dd>Raised when an operation or function receives an argument that has the right type but an inappropriate value, and the situation is not described by a more precise exception such as <a class="reference internal" href="#IndexError" title="IndexError"><code class="xref py py-exc docutils literal notranslate">IndexError</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ZeroDivisionError"> exception ZeroDivisionError<a class="headerlink" href="#ZeroDivisionError" title="Link to this definition">¶</a></dt> <dd>Raised when the second argument of a division or modulo operation is zero. The associated value is a string indicating the type of the operands and the operation. </dd></dl> The following exceptions are kept for compatibility with previous versions; starting from Python 3.3, they are aliases of <a class="reference internal" href="#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate">OSError</code></a>. <dl class="py exception"> <dt class="sig sig-object py" id="EnvironmentError"> exception EnvironmentError<a class="headerlink" href="#EnvironmentError" title="Link to this definition">¶</a></dt> <dd></dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="IOError"> exception IOError<a class="headerlink" href="#IOError" title="Link to this definition">¶</a></dt> <dd></dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="WindowsError"> exception WindowsError<a class="headerlink" href="#WindowsError" title="Link to this definition">¶</a></dt> <dd>Only available on Windows. </dd></dl> <section id="os-exceptions"> <h3>OS exceptions<a class="headerlink" href="#os-exceptions" title="Link to this heading">¶</a></h3> The following exceptions are subclasses of <a class="reference internal" href="#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate">OSError</code></a>, they get raised depending on the system error code. <dl class="py exception"> <dt class="sig sig-object py" id="BlockingIOError"> exception BlockingIOError<a class="headerlink" href="#BlockingIOError" title="Link to this definition">¶</a></dt> <dd>Raised when an operation would block on an object (e.g. socket) set for non-blocking operation. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.EAGAIN" title="errno.EAGAIN"><code class="xref py py-const docutils literal notranslate">EAGAIN</code></a>, <a class="reference internal" href="errno.html#errno.EALREADY" title="errno.EALREADY"><code class="xref py py-const docutils literal notranslate">EALREADY</code></a>, <a class="reference internal" href="errno.html#errno.EWOULDBLOCK" title="errno.EWOULDBLOCK"><code class="xref py py-const docutils literal notranslate">EWOULDBLOCK</code></a> and <a class="reference internal" href="errno.html#errno.EINPROGRESS" title="errno.EINPROGRESS"><code class="xref py py-const docutils literal notranslate">EINPROGRESS</code></a>. In addition to those of <a class="reference internal" href="#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate">OSError</code></a>, <a class="reference internal" href="#BlockingIOError" title="BlockingIOError"><code class="xref py py-exc docutils literal notranslate">BlockingIOError</code></a> can have one more attribute: <dl class="py attribute"> <dt class="sig sig-object py" id="BlockingIOError.characters_written"> characters_written<a class="headerlink" href="#BlockingIOError.characters_written" title="Link to this definition">¶</a></dt> <dd>An integer containing the number of characters written to the stream before it blocked. This attribute is available when using the buffered I/O classes from the <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> module. </dd></dl> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ChildProcessError"> exception ChildProcessError<a class="headerlink" href="#ChildProcessError" title="Link to this definition">¶</a></dt> <dd>Raised when an operation on a child process failed. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.ECHILD" title="errno.ECHILD"><code class="xref py py-const docutils literal notranslate">ECHILD</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ConnectionError"> exception ConnectionError<a class="headerlink" href="#ConnectionError" title="Link to this definition">¶</a></dt> <dd>A base class for connection-related issues. Subclasses are <a class="reference internal" href="#BrokenPipeError" title="BrokenPipeError"><code class="xref py py-exc docutils literal notranslate">BrokenPipeError</code></a>, <a class="reference internal" href="#ConnectionAbortedError" title="ConnectionAbortedError"><code class="xref py py-exc docutils literal notranslate">ConnectionAbortedError</code></a>, <a class="reference internal" href="#ConnectionRefusedError" title="ConnectionRefusedError"><code class="xref py py-exc docutils literal notranslate">ConnectionRefusedError</code></a> and <a class="reference internal" href="#ConnectionResetError" title="ConnectionResetError"><code class="xref py py-exc docutils literal notranslate">ConnectionResetError</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="BrokenPipeError"> exception BrokenPipeError<a class="headerlink" href="#BrokenPipeError" title="Link to this definition">¶</a></dt> <dd>A subclass of <a class="reference internal" href="#ConnectionError" title="ConnectionError"><code class="xref py py-exc docutils literal notranslate">ConnectionError</code></a>, raised when trying to write on a pipe while the other end has been closed, or trying to write on a socket which has been shutdown for writing. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.EPIPE" title="errno.EPIPE"><code class="xref py py-const docutils literal notranslate">EPIPE</code></a> and <a class="reference internal" href="errno.html#errno.ESHUTDOWN" title="errno.ESHUTDOWN"><code class="xref py py-const docutils literal notranslate">ESHUTDOWN</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ConnectionAbortedError"> exception ConnectionAbortedError<a class="headerlink" href="#ConnectionAbortedError" title="Link to this definition">¶</a></dt> <dd>A subclass of <a class="reference internal" href="#ConnectionError" title="ConnectionError"><code class="xref py py-exc docutils literal notranslate">ConnectionError</code></a>, raised when a connection attempt is aborted by the peer. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.ECONNABORTED" title="errno.ECONNABORTED"><code class="xref py py-const docutils literal notranslate">ECONNABORTED</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ConnectionRefusedError"> exception ConnectionRefusedError<a class="headerlink" href="#ConnectionRefusedError" title="Link to this definition">¶</a></dt> <dd>A subclass of <a class="reference internal" href="#ConnectionError" title="ConnectionError"><code class="xref py py-exc docutils literal notranslate">ConnectionError</code></a>, raised when a connection attempt is refused by the peer. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.ECONNREFUSED" title="errno.ECONNREFUSED"><code class="xref py py-const docutils literal notranslate">ECONNREFUSED</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ConnectionResetError"> exception ConnectionResetError<a class="headerlink" href="#ConnectionResetError" title="Link to this definition">¶</a></dt> <dd>A subclass of <a class="reference internal" href="#ConnectionError" title="ConnectionError"><code class="xref py py-exc docutils literal notranslate">ConnectionError</code></a>, raised when a connection is reset by the peer. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.ECONNRESET" title="errno.ECONNRESET"><code class="xref py py-const docutils literal notranslate">ECONNRESET</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="FileExistsError"> exception FileExistsError<a class="headerlink" href="#FileExistsError" title="Link to this definition">¶</a></dt> <dd>Raised when trying to create a file or directory which already exists. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.EEXIST" title="errno.EEXIST"><code class="xref py py-const docutils literal notranslate">EEXIST</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="FileNotFoundError"> exception FileNotFoundError<a class="headerlink" href="#FileNotFoundError" title="Link to this definition">¶</a></dt> <dd>Raised when a file or directory is requested but doesn’t exist. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.ENOENT" title="errno.ENOENT"><code class="xref py py-const docutils literal notranslate">ENOENT</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="InterruptedError"> exception InterruptedError<a class="headerlink" href="#InterruptedError" title="Link to this definition">¶</a></dt> <dd>Raised when a system call is interrupted by an incoming signal. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.EINTR" title="errno.EINTR"><code class="xref py py-const docutils literal notranslate">EINTR</code></a>. <div class="versionchanged"> Changed in version 3.5: Python now retries system calls when a syscall is interrupted by a signal, except if the signal handler raises an exception (see <a class="pep reference external" href="https://peps.python.org/pep-0475/">PEP 475</a> for the rationale), instead of raising <a class="reference internal" href="#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate">InterruptedError</code></a>. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="IsADirectoryError"> exception IsADirectoryError<a class="headerlink" href="#IsADirectoryError" title="Link to this definition">¶</a></dt> <dd>Raised when a file operation (such as <a class="reference internal" href="os.html#os.remove" title="os.remove"><code class="xref py py-func docutils literal notranslate">os.remove()</code></a>) is requested on a directory. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.EISDIR" title="errno.EISDIR"><code class="xref py py-const docutils literal notranslate">EISDIR</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="NotADirectoryError"> exception NotADirectoryError<a class="headerlink" href="#NotADirectoryError" title="Link to this definition">¶</a></dt> <dd>Raised when a directory operation (such as <a class="reference internal" href="os.html#os.listdir" title="os.listdir"><code class="xref py py-func docutils literal notranslate">os.listdir()</code></a>) is requested on something which is not a directory. On most POSIX platforms, it may also be raised if an operation attempts to open or traverse a non-directory file as if it were a directory. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.ENOTDIR" title="errno.ENOTDIR"><code class="xref py py-const docutils literal notranslate">ENOTDIR</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="PermissionError"> exception PermissionError<a class="headerlink" href="#PermissionError" title="Link to this definition">¶</a></dt> <dd>Raised when trying to run an operation without the adequate access rights - for example filesystem permissions. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.EACCES" title="errno.EACCES"><code class="xref py py-const docutils literal notranslate">EACCES</code></a>, <a class="reference internal" href="errno.html#errno.EPERM" title="errno.EPERM"><code class="xref py py-const docutils literal notranslate">EPERM</code></a>, and <a class="reference internal" href="errno.html#errno.ENOTCAPABLE" title="errno.ENOTCAPABLE"><code class="xref py py-const docutils literal notranslate">ENOTCAPABLE</code></a>. <div class="versionchanged"> Changed in version 3.11.1: WASI’s <a class="reference internal" href="errno.html#errno.ENOTCAPABLE" title="errno.ENOTCAPABLE"><code class="xref py py-const docutils literal notranslate">ENOTCAPABLE</code></a> is now mapped to <a class="reference internal" href="#PermissionError" title="PermissionError"><code class="xref py py-exc docutils literal notranslate">PermissionError</code></a>. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ProcessLookupError"> exception ProcessLookupError<a class="headerlink" href="#ProcessLookupError" title="Link to this definition">¶</a></dt> <dd>Raised when a given process doesn’t exist. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.ESRCH" title="errno.ESRCH"><code class="xref py py-const docutils literal notranslate">ESRCH</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="TimeoutError"> exception TimeoutError<a class="headerlink" href="#TimeoutError" title="Link to this definition">¶</a></dt> <dd>Raised when a system function timed out at the system level. Corresponds to <code class="xref c c-data docutils literal notranslate">errno</code> <a class="reference internal" href="errno.html#errno.ETIMEDOUT" title="errno.ETIMEDOUT"><code class="xref py py-const docutils literal notranslate">ETIMEDOUT</code></a>. </dd></dl> <div class="versionadded"> Added in version 3.3: All the above <a class="reference internal" href="#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate">OSError</code></a> subclasses were added. </div> <div class="admonition seealso"> See also <a class="pep reference external" href="https://peps.python.org/pep-3151/">PEP 3151</a> - Reworking the OS and IO exception hierarchy </div> </section> </section> <section id="warnings"> <h2>Warnings<a class="headerlink" href="#warnings" title="Link to this heading">¶</a></h2> The following exceptions are used as warning categories; see the <a class="reference internal" href="warnings.html#warning-categories">Warning Categories</a> documentation for more details. <dl class="py exception"> <dt class="sig sig-object py" id="Warning"> exception Warning<a class="headerlink" href="#Warning" title="Link to this definition">¶</a></dt> <dd>Base class for warning categories. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="UserWarning"> exception UserWarning<a class="headerlink" href="#UserWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings generated by user code. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="DeprecationWarning"> exception DeprecationWarning<a class="headerlink" href="#DeprecationWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings about deprecated features when those warnings are intended for other Python developers. Ignored by the default warning filters, except in the <code class="docutils literal notranslate">__main__</code> module (<a class="pep reference external" href="https://peps.python.org/pep-0565/">PEP 565</a>). Enabling the <a class="reference internal" href="devmode.html#devmode">Python Development Mode</a> shows this warning. The deprecation policy is described in <a class="pep reference external" href="https://peps.python.org/pep-0387/">PEP 387</a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="PendingDeprecationWarning"> exception PendingDeprecationWarning<a class="headerlink" href="#PendingDeprecationWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings about features which are obsolete and expected to be deprecated in the future, but are not deprecated at the moment. This class is rarely used as emitting a warning about a possible upcoming deprecation is unusual, and <a class="reference internal" href="#DeprecationWarning" title="DeprecationWarning"><code class="xref py py-exc docutils literal notranslate">DeprecationWarning</code></a> is preferred for already active deprecations. Ignored by the default warning filters. Enabling the <a class="reference internal" href="devmode.html#devmode">Python Development Mode</a> shows this warning. The deprecation policy is described in <a class="pep reference external" href="https://peps.python.org/pep-0387/">PEP 387</a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="SyntaxWarning"> exception SyntaxWarning<a class="headerlink" href="#SyntaxWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings about dubious syntax. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="RuntimeWarning"> exception RuntimeWarning<a class="headerlink" href="#RuntimeWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings about dubious runtime behavior. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="FutureWarning"> exception FutureWarning<a class="headerlink" href="#FutureWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings about deprecated features when those warnings are intended for end users of applications that are written in Python. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ImportWarning"> exception ImportWarning<a class="headerlink" href="#ImportWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings about probable mistakes in module imports. Ignored by the default warning filters. Enabling the <a class="reference internal" href="devmode.html#devmode">Python Development Mode</a> shows this warning. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="UnicodeWarning"> exception UnicodeWarning<a class="headerlink" href="#UnicodeWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings related to Unicode. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="EncodingWarning"> exception EncodingWarning<a class="headerlink" href="#EncodingWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings related to encodings. See <a class="reference internal" href="io.html#io-encoding-warning">Opt-in EncodingWarning</a> for details. <div class="versionadded"> Added in version 3.10. </div> </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="BytesWarning"> exception BytesWarning<a class="headerlink" href="#BytesWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings related to <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate">bytes</code></a> and <a class="reference internal" href="stdtypes.html#bytearray" title="bytearray"><code class="xref py py-class docutils literal notranslate">bytearray</code></a>. </dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="ResourceWarning"> exception ResourceWarning<a class="headerlink" href="#ResourceWarning" title="Link to this definition">¶</a></dt> <dd>Base class for warnings related to resource usage. Ignored by the default warning filters. Enabling the <a class="reference internal" href="devmode.html#devmode">Python Development Mode</a> shows this warning. <div class="versionadded"> Added in version 3.2. </div> </dd></dl> </section> <section id="exception-groups"> <h2>Exception groups<a class="headerlink" href="#exception-groups" title="Link to this heading">¶</a></h2> The following are used when it is necessary to raise multiple unrelated exceptions. They are part of the exception hierarchy so they can be handled with <a class="reference internal" href="../reference/compound_stmts.html#except"><code class="xref std std-keyword docutils literal notranslate">except</code></a> like all other exceptions. In addition, they are recognised by <a class="reference internal" href="../reference/compound_stmts.html#except-star"><code class="xref std std-keyword docutils literal notranslate">except*</code></a>, which matches their subgroups based on the types of the contained exceptions. <dl class="py exception"> <dt class="sig sig-object py" id="ExceptionGroup"> exception ExceptionGroup(msg, excs)<a class="headerlink" href="#ExceptionGroup" title="Link to this definition">¶</a></dt> <dd></dd></dl> <dl class="py exception"> <dt class="sig sig-object py" id="BaseExceptionGroup"> exception BaseExceptionGroup(msg, excs)<a class="headerlink" href="#BaseExceptionGroup" title="Link to this definition">¶</a></dt> <dd>Both of these exception types wrap the exceptions in the sequence <code class="docutils literal notranslate">excs</code>. The <code class="docutils literal notranslate">msg</code> parameter must be a string. The difference between the two classes is that <a class="reference internal" href="#BaseExceptionGroup" title="BaseExceptionGroup"><code class="xref py py-exc docutils literal notranslate">BaseExceptionGroup</code></a> extends <a class="reference internal" href="#BaseException" title="BaseException"><code class="xref py py-exc docutils literal notranslate">BaseException</code></a> and it can wrap any exception, while <a class="reference internal" href="#ExceptionGroup" title="ExceptionGroup"><code class="xref py py-exc docutils literal notranslate">ExceptionGroup</code></a> extends <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a> and it can only wrap subclasses of <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a>. This design is so that <code class="docutils literal notranslate">except Exception</code> catches an <a class="reference internal" href="#ExceptionGroup" title="ExceptionGroup"><code class="xref py py-exc docutils literal notranslate">ExceptionGroup</code></a> but not <a class="reference internal" href="#BaseExceptionGroup" title="BaseExceptionGroup"><code class="xref py py-exc docutils literal notranslate">BaseExceptionGroup</code></a>. The <a class="reference internal" href="#BaseExceptionGroup" title="BaseExceptionGroup"><code class="xref py py-exc docutils literal notranslate">BaseExceptionGroup</code></a> constructor returns an <a class="reference internal" href="#ExceptionGroup" title="ExceptionGroup"><code class="xref py py-exc docutils literal notranslate">ExceptionGroup</code></a> rather than a <a class="reference internal" href="#BaseExceptionGroup" title="BaseExceptionGroup"><code class="xref py py-exc docutils literal notranslate">BaseExceptionGroup</code></a> if all contained exceptions are <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a> instances, so it can be used to make the selection automatic. The <a class="reference internal" href="#ExceptionGroup" title="ExceptionGroup"><code class="xref py py-exc docutils literal notranslate">ExceptionGroup</code></a> constructor, on the other hand, raises a <a class="reference internal" href="#TypeError" title="TypeError"><code class="xref py py-exc docutils literal notranslate">TypeError</code></a> if any contained exception is not an <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a> subclass. <dl class="py attribute"> <dt class="sig sig-object py" id="BaseExceptionGroup.message"> message<a class="headerlink" href="#BaseExceptionGroup.message" title="Link to this definition">¶</a></dt> <dd>The <code class="docutils literal notranslate">msg</code> argument to the constructor. This is a read-only attribute. </dd></dl> <dl class="py attribute"> <dt class="sig sig-object py" id="BaseExceptionGroup.exceptions"> exceptions<a class="headerlink" href="#BaseExceptionGroup.exceptions" title="Link to this definition">¶</a></dt> <dd>A tuple of the exceptions in the <code class="docutils literal notranslate">excs</code> sequence given to the constructor. This is a read-only attribute. </dd></dl> <dl class="py method"> <dt class="sig sig-object py" id="BaseExceptionGroup.subgroup"> subgroup(condition)<a class="headerlink" href="#BaseExceptionGroup.subgroup" title="Link to this definition">¶</a></dt> <dd>Returns an exception group that contains only the exceptions from the current group that match condition, or <code class="docutils literal notranslate">None</code> if the result is empty. The condition can be an exception type or tuple of exception types, in which case each exception is checked for a match using the same check that is used in an <code class="docutils literal notranslate">except</code> clause. The condition can also be a callable (other than a type object) that accepts an exception as its single argument and returns true for the exceptions that should be in the subgroup. The nesting structure of the current exception is preserved in the result, as are the values of its <a class="reference internal" href="#BaseExceptionGroup.message" title="BaseExceptionGroup.message"><code class="xref py py-attr docutils literal notranslate">message</code></a>, <a class="reference internal" href="#BaseException.__traceback__" title="BaseException.__traceback__"><code class="xref py py-attr docutils literal notranslate">__traceback__</code></a>, <a class="reference internal" href="#BaseException.__cause__" title="BaseException.__cause__"><code class="xref py py-attr docutils literal notranslate">__cause__</code></a>, <a class="reference internal" href="#BaseException.__context__" title="BaseException.__context__"><code class="xref py py-attr docutils literal notranslate">__context__</code></a> and <a class="reference internal" href="#BaseException.__notes__" title="BaseException.__notes__"><code class="xref py py-attr docutils literal notranslate">__notes__</code></a> fields. Empty nested groups are omitted from the result. The condition is checked for all exceptions in the nested exception group, including the top-level and any nested exception groups. If the condition is true for such an exception group, it is included in the result in full. <div class="versionadded"> Added in version 3.13: <code class="docutils literal notranslate">condition</code> can be any callable which is not a type object. </div> </dd></dl> <dl class="py method"> <dt class="sig sig-object py" id="BaseExceptionGroup.split"> split(condition)<a class="headerlink" href="#BaseExceptionGroup.split" title="Link to this definition">¶</a></dt> <dd>Like <a class="reference internal" href="#BaseExceptionGroup.subgroup" title="BaseExceptionGroup.subgroup"><code class="xref py py-meth docutils literal notranslate">subgroup()</code></a>, but returns the pair <code class="docutils literal notranslate">(match, rest)</code> where <code class="docutils literal notranslate">match</code> is <code class="docutils literal notranslate">subgroup(condition)</code> and <code class="docutils literal notranslate">rest</code> is the remaining non-matching part. </dd></dl> <dl class="py method"> <dt class="sig sig-object py" id="BaseExceptionGroup.derive"> derive(excs)<a class="headerlink" href="#BaseExceptionGroup.derive" title="Link to this definition">¶</a></dt> <dd>Returns an exception group with the same <a class="reference internal" href="#BaseExceptionGroup.message" title="BaseExceptionGroup.message"><code class="xref py py-attr docutils literal notranslate">message</code></a>, but which wraps the exceptions in <code class="docutils literal notranslate">excs</code>. This method is used by <a class="reference internal" href="#BaseExceptionGroup.subgroup" title="BaseExceptionGroup.subgroup"><code class="xref py py-meth docutils literal notranslate">subgroup()</code></a> and <a class="reference internal" href="#BaseExceptionGroup.split" title="BaseExceptionGroup.split"><code class="xref py py-meth docutils literal notranslate">split()</code></a>, which are used in various contexts to break up an exception group. A subclass needs to override it in order to make <a class="reference internal" href="#BaseExceptionGroup.subgroup" title="BaseExceptionGroup.subgroup"><code class="xref py py-meth docutils literal notranslate">subgroup()</code></a> and <a class="reference internal" href="#BaseExceptionGroup.split" title="BaseExceptionGroup.split"><code class="xref py py-meth docutils literal notranslate">split()</code></a> return instances of the subclass rather than <a class="reference internal" href="#ExceptionGroup" title="ExceptionGroup"><code class="xref py py-exc docutils literal notranslate">ExceptionGroup</code></a>. <a class="reference internal" href="#BaseExceptionGroup.subgroup" title="BaseExceptionGroup.subgroup"><code class="xref py py-meth docutils literal notranslate">subgroup()</code></a> and <a class="reference internal" href="#BaseExceptionGroup.split" title="BaseExceptionGroup.split"><code class="xref py py-meth docutils literal notranslate">split()</code></a> copy the <a class="reference internal" href="#BaseException.__traceback__" title="BaseException.__traceback__"><code class="xref py py-attr docutils literal notranslate">__traceback__</code></a>, <a class="reference internal" href="#BaseException.__cause__" title="BaseException.__cause__"><code class="xref py py-attr docutils literal notranslate">__cause__</code></a>, <a class="reference internal" href="#BaseException.__context__" title="BaseException.__context__"><code class="xref py py-attr docutils literal notranslate">__context__</code></a> and <a class="reference internal" href="#BaseException.__notes__" title="BaseException.__notes__"><code class="xref py py-attr docutils literal notranslate">__notes__</code></a> fields from the original exception group to the one returned by <a class="reference internal" href="#BaseExceptionGroup.derive" title="BaseExceptionGroup.derive"><code class="xref py py-meth docutils literal notranslate">derive()</code></a>, so these fields do not need to be updated by <a class="reference internal" href="#BaseExceptionGroup.derive" title="BaseExceptionGroup.derive"><code class="xref py py-meth docutils literal notranslate">derive()</code></a>. <div class="highlight-pycon notranslate"><div class="highlight"><pre>>>> class MyGroup(ExceptionGroup): ... def derive(self, excs): ... return MyGroup(self.message, excs) ... >>> e = MyGroup("eg", [ValueError(1), TypeError(2)]) >>> e.add_note("a note") >>> e.__context__ = Exception("context") >>> e.__cause__ = Exception("cause") >>> try: ... raise e ... except Exception as e: ... exc = e ... >>> match, rest = exc.split(ValueError) >>> exc, exc.__context__, exc.__cause__, exc.__notes__ (MyGroup('eg', [ValueError(1), TypeError(2)]), Exception('context'), Exception('cause'), ['a note']) >>> match, match.__context__, match.__cause__, match.__notes__ (MyGroup('eg', [ValueError(1)]), Exception('context'), Exception('cause'), ['a note']) >>> rest, rest.__context__, rest.__cause__, rest.__notes__ (MyGroup('eg', [TypeError(2)]), Exception('context'), Exception('cause'), ['a note']) >>> exc.__traceback__ is match.__traceback__ is rest.__traceback__ True </pre></div> </div> </dd></dl> Note that <a class="reference internal" href="#BaseExceptionGroup" title="BaseExceptionGroup"><code class="xref py py-exc docutils literal notranslate">BaseExceptionGroup</code></a> defines <a class="reference internal" href="../reference/datamodel.html#object.__new__" title="object.__new__"><code class="xref py py-meth docutils literal notranslate">__new__()</code></a>, so subclasses that need a different constructor signature need to override that rather than <a class="reference internal" href="../reference/datamodel.html#object.__init__" title="object.__init__"><code class="xref py py-meth docutils literal notranslate">__init__()</code></a>. For example, the following defines an exception group subclass which accepts an exit_code and and constructs the group’s message from it. <div class="highlight-python3 notranslate"><div class="highlight"><pre>class Errors(ExceptionGroup): def __new__(cls, errors, exit_code): self = super().__new__(Errors, f"exit code: {exit_code}", errors) self.exit_code = exit_code return self def derive(self, excs): return Errors(excs, self.exit_code) </pre></div> </div> Like <a class="reference internal" href="#ExceptionGroup" title="ExceptionGroup"><code class="xref py py-exc docutils literal notranslate">ExceptionGroup</code></a>, any subclass of <a class="reference internal" href="#BaseExceptionGroup" title="BaseExceptionGroup"><code class="xref py py-exc docutils literal notranslate">BaseExceptionGroup</code></a> which is also a subclass of <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a> can only wrap instances of <a class="reference internal" href="#Exception" title="Exception"><code class="xref py py-exc docutils literal notranslate">Exception</code></a>. <div class="versionadded"> Added in version 3.11. </div> </dd></dl> </section> <section id="exception-hierarchy"> <h2>Exception hierarchy<a class="headerlink" href="#exception-hierarchy" title="Link to this heading">¶</a></h2> The class hierarchy for built-in exceptions is: <div class="highlight-text notranslate"><div class="highlight"><pre>BaseException ├── BaseExceptionGroup ├── GeneratorExit ├── KeyboardInterrupt ├── SystemExit └── Exception ├── ArithmeticError │ ├── FloatingPointError │ ├── OverflowError │ └── ZeroDivisionError ├── AssertionError ├── AttributeError ├── BufferError ├── EOFError ├── ExceptionGroup [BaseExceptionGroup] ├── ImportError │ └── ModuleNotFoundError ├── LookupError │ ├── IndexError │ └── KeyError ├── MemoryError ├── NameError │ └── UnboundLocalError ├── OSError │ ├── BlockingIOError │ ├── ChildProcessError │ ├── ConnectionError │ │ ├── BrokenPipeError │ │ ├── ConnectionAbortedError │ │ ├── ConnectionRefusedError │ │ └── ConnectionResetError │ ├── FileExistsError │ ├── FileNotFoundError │ ├── InterruptedError │ ├── IsADirectoryError │ ├── NotADirectoryError │ ├── PermissionError │ ├── ProcessLookupError │ └── TimeoutError ├── ReferenceError ├── RuntimeError │ ├── NotImplementedError │ ├── PythonFinalizationError │ └── RecursionError ├── StopAsyncIteration ├── StopIteration ├── SyntaxError │ └── IndentationError │ └── TabError ├── SystemError ├── TypeError ├── ValueError │ └── UnicodeError │ ├── UnicodeDecodeError │ ├── UnicodeEncodeError │ └── UnicodeTranslateError └── Warning ├── BytesWarning ├── DeprecationWarning ├── EncodingWarning ├── FutureWarning ├── ImportWarning ├── PendingDeprecationWarning ├── ResourceWarning ├── RuntimeWarning ├── SyntaxWarning ├── UnicodeWarning └── UserWarning </pre></div> </div> </section> </section> <div class="clearer"></div> </div> </div> </div> <div class="sphinxsidebar" role="navigation" aria-label="Main"> <div class="sphinxsidebarwrapper"> <div> <h3><a href="../contents.html">Table of Contents</a></h3> <ul> <li><a class="reference internal" href="#">Built-in Exceptions</a><ul> <li><a class="reference internal" href="#exception-context">Exception context</a><ul> <li><a class="reference internal" href="#BaseException.__context__"><code class="docutils literal notranslate">__context__</code></a></li> <li><a class="reference internal" href="#BaseException.__cause__"><code class="docutils literal notranslate">__cause__</code></a></li> <li><a class="reference internal" href="#BaseException.__suppress_context__"><code class="docutils literal notranslate">__suppress_context__</code></a></li> </ul> </li> <li><a class="reference internal" href="#inheriting-from-built-in-exceptions">Inheriting from built-in exceptions</a></li> <li><a class="reference internal" href="#base-classes">Base classes</a><ul> <li><a class="reference internal" href="#BaseException"><code class="docutils literal notranslate">BaseException</code></a><ul> <li><a class="reference internal" href="#BaseException.args"><code class="docutils literal notranslate">args</code></a></li> <li><a class="reference internal" href="#BaseException.with_traceback"><code class="docutils literal notranslate">with_traceback()</code></a></li> <li><a class="reference internal" href="#BaseException.__traceback__"><code class="docutils literal notranslate">__traceback__</code></a></li> <li><a class="reference internal" href="#BaseException.add_note"><code class="docutils literal notranslate">add_note()</code></a></li> <li><a class="reference internal" href="#BaseException.__notes__"><code class="docutils literal notranslate">__notes__</code></a></li> </ul> </li> <li><a class="reference internal" href="#Exception"><code class="docutils literal notranslate">Exception</code></a></li> <li><a class="reference internal" href="#ArithmeticError"><code class="docutils literal notranslate">ArithmeticError</code></a></li> <li><a class="reference internal" href="#BufferError"><code class="docutils literal notranslate">BufferError</code></a></li> <li><a class="reference internal" href="#LookupError"><code class="docutils literal notranslate">LookupError</code></a></li> </ul> </li> <li><a class="reference internal" href="#concrete-exceptions">Concrete exceptions</a><ul> <li><a class="reference internal" href="#AssertionError"><code class="docutils literal notranslate">AssertionError</code></a></li> <li><a class="reference internal" href="#AttributeError"><code class="docutils literal notranslate">AttributeError</code></a></li> <li><a class="reference internal" href="#EOFError"><code class="docutils literal notranslate">EOFError</code></a></li> <li><a class="reference internal" href="#FloatingPointError"><code class="docutils literal notranslate">FloatingPointError</code></a></li> <li><a class="reference internal" href="#GeneratorExit"><code class="docutils literal notranslate">GeneratorExit</code></a></li> <li><a class="reference internal" href="#ImportError"><code class="docutils literal notranslate">ImportError</code></a><ul> <li><a class="reference internal" href="#ImportError.name"><code class="docutils literal notranslate">name</code></a></li> <li><a class="reference internal" href="#ImportError.path"><code class="docutils literal notranslate">path</code></a></li> </ul> </li> <li><a class="reference internal" href="#ModuleNotFoundError"><code class="docutils literal notranslate">ModuleNotFoundError</code></a></li> <li><a class="reference internal" href="#IndexError"><code class="docutils literal notranslate">IndexError</code></a></li> <li><a class="reference internal" href="#KeyError"><code class="docutils literal notranslate">KeyError</code></a></li> <li><a class="reference internal" href="#KeyboardInterrupt"><code class="docutils literal notranslate">KeyboardInterrupt</code></a></li> <li><a class="reference internal" href="#MemoryError"><code class="docutils literal notranslate">MemoryError</code></a></li> <li><a class="reference internal" href="#NameError"><code class="docutils literal notranslate">NameError</code></a></li> <li><a class="reference internal" href="#NotImplementedError"><code class="docutils literal notranslate">NotImplementedError</code></a></li> <li><a class="reference internal" href="#OSError"><code class="docutils literal notranslate">OSError</code></a><ul> <li><a class="reference internal" href="#OSError.errno"><code class="docutils literal notranslate">errno</code></a></li> <li><a class="reference internal" href="#OSError.winerror"><code class="docutils literal notranslate">winerror</code></a></li> <li><a class="reference internal" href="#OSError.strerror"><code class="docutils literal notranslate">strerror</code></a></li> <li><a class="reference internal" href="#OSError.filename"><code class="docutils literal notranslate">filename</code></a></li> <li><a class="reference internal" href="#OSError.filename2"><code class="docutils literal notranslate">filename2</code></a></li> </ul> </li> <li><a class="reference internal" href="#OverflowError"><code class="docutils literal notranslate">OverflowError</code></a></li> <li><a class="reference internal" href="#PythonFinalizationError"><code class="docutils literal notranslate">PythonFinalizationError</code></a></li> <li><a class="reference internal" href="#RecursionError"><code class="docutils literal notranslate">RecursionError</code></a></li> <li><a class="reference internal" href="#ReferenceError"><code class="docutils literal notranslate">ReferenceError</code></a></li> <li><a class="reference internal" href="#RuntimeError"><code class="docutils literal notranslate">RuntimeError</code></a></li> <li><a class="reference internal" href="#StopIteration"><code class="docutils literal notranslate">StopIteration</code></a><ul> <li><a class="reference internal" href="#StopIteration.value"><code class="docutils literal notranslate">value</code></a></li> </ul> </li> <li><a class="reference internal" href="#StopAsyncIteration"><code class="docutils literal notranslate">StopAsyncIteration</code></a></li> <li><a class="reference internal" href="#SyntaxError"><code class="docutils literal notranslate">SyntaxError</code></a><ul> <li><a class="reference internal" href="#SyntaxError.filename"><code class="docutils literal notranslate">filename</code></a></li> <li><a class="reference internal" href="#SyntaxError.lineno"><code class="docutils literal notranslate">lineno</code></a></li> <li><a class="reference internal" href="#SyntaxError.offset"><code class="docutils literal notranslate">offset</code></a></li> <li><a class="reference internal" href="#SyntaxError.text"><code class="docutils literal notranslate">text</code></a></li> <li><a class="reference internal" href="#SyntaxError.end_lineno"><code class="docutils literal notranslate">end_lineno</code></a></li> <li><a class="reference internal" href="#SyntaxError.end_offset"><code class="docutils literal notranslate">end_offset</code></a></li> </ul> </li> <li><a class="reference internal" href="#IndentationError"><code class="docutils literal notranslate">IndentationError</code></a></li> <li><a class="reference internal" href="#TabError"><code class="docutils literal notranslate">TabError</code></a></li> <li><a class="reference internal" href="#SystemError"><code class="docutils literal notranslate">SystemError</code></a></li> <li><a class="reference internal" href="#SystemExit"><code class="docutils literal notranslate">SystemExit</code></a><ul> <li><a class="reference internal" href="#SystemExit.code"><code class="docutils literal notranslate">code</code></a></li> </ul> </li> <li><a class="reference internal" href="#TypeError"><code class="docutils literal notranslate">TypeError</code></a></li> <li><a class="reference internal" href="#UnboundLocalError"><code class="docutils literal notranslate">UnboundLocalError</code></a></li> <li><a class="reference internal" href="#UnicodeError"><code class="docutils literal notranslate">UnicodeError</code></a><ul> <li><a class="reference internal" href="#UnicodeError.encoding"><code class="docutils literal notranslate">encoding</code></a></li> <li><a class="reference internal" href="#UnicodeError.reason"><code class="docutils literal notranslate">reason</code></a></li> <li><a class="reference internal" href="#UnicodeError.object"><code class="docutils literal notranslate">object</code></a></li> <li><a class="reference internal" href="#UnicodeError.start"><code class="docutils literal notranslate">start</code></a></li> <li><a class="reference internal" href="#UnicodeError.end"><code class="docutils literal notranslate">end</code></a></li> </ul> </li> <li><a class="reference internal" href="#UnicodeEncodeError"><code class="docutils literal notranslate">UnicodeEncodeError</code></a></li> <li><a class="reference internal" href="#UnicodeDecodeError"><code class="docutils literal notranslate">UnicodeDecodeError</code></a></li> <li><a class="reference internal" href="#UnicodeTranslateError"><code class="docutils literal notranslate">UnicodeTranslateError</code></a></li> <li><a class="reference internal" href="#ValueError"><code class="docutils literal notranslate">ValueError</code></a></li> <li><a class="reference internal" href="#ZeroDivisionError"><code class="docutils literal notranslate">ZeroDivisionError</code></a></li> <li><a class="reference internal" href="#EnvironmentError"><code class="docutils literal notranslate">EnvironmentError</code></a></li> <li><a class="reference internal" href="#IOError"><code class="docutils literal notranslate">IOError</code></a></li> <li><a class="reference internal" href="#WindowsError"><code class="docutils literal notranslate">WindowsError</code></a></li> <li><a class="reference internal" href="#os-exceptions">OS exceptions</a><ul> <li><a class="reference internal" href="#BlockingIOError"><code class="docutils literal notranslate">BlockingIOError</code></a><ul> <li><a class="reference internal" href="#BlockingIOError.characters_written"><code class="docutils literal notranslate">characters_written</code></a></li> </ul> </li> <li><a class="reference internal" href="#ChildProcessError"><code class="docutils literal notranslate">ChildProcessError</code></a></li> <li><a class="reference internal" href="#ConnectionError"><code class="docutils literal notranslate">ConnectionError</code></a></li> <li><a class="reference internal" href="#BrokenPipeError"><code class="docutils literal notranslate">BrokenPipeError</code></a></li> <li><a class="reference internal" href="#ConnectionAbortedError"><code class="docutils literal notranslate">ConnectionAbortedError</code></a></li> <li><a class="reference internal" href="#ConnectionRefusedError"><code class="docutils literal notranslate">ConnectionRefusedError</code></a></li> <li><a class="reference internal" href="#ConnectionResetError"><code class="docutils literal notranslate">ConnectionResetError</code></a></li> <li><a class="reference internal" href="#FileExistsError"><code class="docutils literal notranslate">FileExistsError</code></a></li> <li><a class="reference internal" href="#FileNotFoundError"><code class="docutils literal notranslate">FileNotFoundError</code></a></li> <li><a class="reference internal" href="#InterruptedError"><code class="docutils literal notranslate">InterruptedError</code></a></li> <li><a class="reference internal" href="#IsADirectoryError"><code class="docutils literal notranslate">IsADirectoryError</code></a></li> <li><a class="reference internal" href="#NotADirectoryError"><code class="docutils literal notranslate">NotADirectoryError</code></a></li> <li><a class="reference internal" href="#PermissionError"><code class="docutils literal notranslate">PermissionError</code></a></li> <li><a class="reference internal" href="#ProcessLookupError"><code class="docutils literal notranslate">ProcessLookupError</code></a></li> <li><a class="reference internal" href="#TimeoutError"><code class="docutils literal notranslate">TimeoutError</code></a></li> </ul> </li> </ul> </li> <li><a class="reference internal" href="#warnings">Warnings</a><ul> <li><a class="reference internal" href="#Warning"><code class="docutils literal notranslate">Warning</code></a></li> <li><a class="reference internal" href="#UserWarning"><code class="docutils literal notranslate">UserWarning</code></a></li> <li><a class="reference internal" href="#DeprecationWarning"><code class="docutils literal notranslate">DeprecationWarning</code></a></li> <li><a class="reference internal" href="#PendingDeprecationWarning"><code class="docutils literal notranslate">PendingDeprecationWarning</code></a></li> <li><a class="reference internal" href="#SyntaxWarning"><code class="docutils literal notranslate">SyntaxWarning</code></a></li> <li><a class="reference internal" href="#RuntimeWarning"><code class="docutils literal notranslate">RuntimeWarning</code></a></li> <li><a class="reference internal" href="#FutureWarning"><code class="docutils literal notranslate">FutureWarning</code></a></li> <li><a class="reference internal" href="#ImportWarning"><code class="docutils literal notranslate">ImportWarning</code></a></li> <li><a class="reference internal" href="#UnicodeWarning"><code class="docutils literal notranslate">UnicodeWarning</code></a></li> <li><a class="reference internal" href="#EncodingWarning"><code class="docutils literal notranslate">EncodingWarning</code></a></li> <li><a class="reference internal" href="#BytesWarning"><code class="docutils literal notranslate">BytesWarning</code></a></li> <li><a class="reference internal" href="#ResourceWarning"><code class="docutils literal notranslate">ResourceWarning</code></a></li> </ul> </li> <li><a class="reference internal" href="#exception-groups">Exception groups</a><ul> <li><a class="reference internal" href="#ExceptionGroup"><code class="docutils literal notranslate">ExceptionGroup</code></a></li> <li><a class="reference internal" href="#BaseExceptionGroup"><code class="docutils literal notranslate">BaseExceptionGroup</code></a><ul> <li><a class="reference internal" href="#BaseExceptionGroup.message"><code class="docutils literal notranslate">message</code></a></li> <li><a class="reference internal" href="#BaseExceptionGroup.exceptions"><code class="docutils literal notranslate">exceptions</code></a></li> <li><a class="reference internal" href="#BaseExceptionGroup.subgroup"><code class="docutils literal notranslate">subgroup()</code></a></li> <li><a class="reference internal" href="#BaseExceptionGroup.split"><code class="docutils literal notranslate">split()</code></a></li> <li><a class="reference internal" href="#BaseExceptionGroup.derive"><code class="docutils literal notranslate">derive()</code></a></li> </ul> </li> </ul> </li> <li><a class="reference internal" href="#exception-hierarchy">Exception hierarchy</a></li> </ul> </li> </ul> </div> <div> <h4>Previous topic</h4> <a href="stdtypes.html" title="previous chapter">Built-in Types</a> </div> <div> <h4>Next topic</h4> <a href="text.html" title="next chapter">Text Processing Services</a> </div> <div role="note" aria-label="source link"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li> <a href="https://github.com/python/cpython/blob/main/Doc/library/exceptions.rst" rel="nofollow">Show Source </a> </li> </ul> </div> </div> <div id="sidebarbutton" title="Collapse sidebar"> « </div> </div> <div class="clearer"></div> </div> <div class="related" role="navigation" aria-label="Related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="../genindex.html" title="General Index" >index</a></li> <li class="right" > <a 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