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aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://medium.com/dartlang" target="_blank" rel="noopener"><div><span>Blog</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://dartpad.dev" target="_blank" rel="noopener"><div><span>DartPad (online editor)</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://flutter.dev" target="_blank" rel="noopener"><div><span>Flutter</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li><li class="nav-item"><a class="nav-link" href="https://pub.dev" target="_blank" rel="noopener"><div><span>Package site</span><span class="material-symbols" aria-hidden="true">open_in_new</span></div></a></li></ul></li></ul></div><main id="page-content"><div id="site-toc--side" class="site-toc"><header class="site-toc__title">Contents</header><ul class="section-nav"><li class="toc-entry nav-item"><a class="nav-link" href="#for-loops">For loops</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#while-and-do-while">While and do-while</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#break-and-continue">Break and continue</a></li><li class="toc-entry nav-item"><a class="nav-link" href="#labels">Labels</a></li></ul></div><article><div class="content"><div id="site-content-title"><h1>Loops</h1></div><div id="site-toc--inline" class="site-toc"><header class="site-toc__title">Contents</header><ul class="section-nav"><li class="toc-entry"><a href="#for-loops">For loops</a></li><li class="toc-entry"><a href="#while-and-do-while">While and do-while</a></li><li class="toc-entry"><a href="#break-and-continue">Break and continue</a></li><li class="toc-entry"><a href="#labels">Labels</a></li></ul></div><p>This page shows how you can control the flow of your Dart code using loops and supporting statements:</p><ul><li><code>for</code> loops</li><li><code>while</code> and <code>do while</code> loops</li><li><code>break</code> and <code>continue</code></li></ul><p>You can also manipulate control flow in Dart using:</p><ul><li><a href="/language/branches">Branching</a>, like <code>if</code> and <code>switch</code></li><li><a href="/language/error-handling">Exceptions</a>, like <code>try</code>, <code>catch</code>, and <code>throw</code></li></ul><div class="header-wrapper"><h2 id="for-loops">For loops</h2><a class="heading-link" href="#for-loops" aria-label="Link to 'For loops' section">#</a></div><p>You can iterate with the standard <code>for</code> loop. For example:</p> <?code-excerpt "language/test/control_flow/loops_test.dart (for)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">var</span><span style="color:#222222"> message = </span><span style="color:#0468D7">StringBuffer</span><span style="color:#222222">(</span><span style="color:#11796D">'Dart is fun'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#D43324">for</span><span style="color:#222222"> (</span><span style="color:#D43324">var</span><span style="color:#222222"> i = </span><span style="color:#11796D">0</span><span style="color:#222222">; i < </span><span style="color:#11796D">5</span><span style="color:#222222">; i++) {</span></span> <span class="line"><span style="color:#222222"> message.</span><span style="color:#6200EE">write</span><span style="color:#222222">(</span><span style="color:#11796D">'!'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>Closures inside of Dart's <code>for</code> loops capture the <em>value</em> of the index. This avoids a common pitfall found in JavaScript. For example, consider:</p> <?code-excerpt "language/test/control_flow/loops_test.dart (for-and-closures)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">var</span><span style="color:#222222"> callbacks = [];</span></span> <span class="line"><span style="color:#D43324">for</span><span style="color:#222222"> (</span><span style="color:#D43324">var</span><span style="color:#222222"> i = </span><span style="color:#11796D">0</span><span style="color:#222222">; i < </span><span style="color:#11796D">2</span><span style="color:#222222">; i++) {</span></span> <span class="line"><span style="color:#222222"> callbacks.</span><span style="color:#6200EE">add</span><span style="color:#222222">(() => </span><span style="color:#6200EE">print</span><span style="color:#222222">(i));</span></span> <span class="line"><span style="color:#222222">}</span></span> <span class="line"></span> <span class="line"><span style="color:#D43324">for</span><span style="color:#222222"> (</span><span style="color:#D43324">final</span><span style="color:#222222"> c </span><span style="color:#D43324">in</span><span style="color:#222222"> callbacks) {</span></span> <span class="line"><span style="color:#6200EE"> c</span><span style="color:#222222">();</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>The output is <code>0</code> and then <code>1</code>, as expected. In contrast, the example would print <code>2</code> and then <code>2</code> in JavaScript.</p><p>Sometimes you might not need to know the current iteration counter when iterating over an <a href="https://api.dart.dev/dart-core/Iterable-class.html"><code>Iterable</code></a> type, like <code>List</code> or <code>Set</code>. In that case, use the <code>for-in</code> loop for cleaner code:</p> <?code-excerpt "language/lib/control_flow/loops.dart (collection)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">for</span><span style="color:#222222"> (</span><span style="color:#D43324">final</span><span style="color:#222222"> candidate </span><span style="color:#D43324">in</span><span style="color:#222222"> candidates) {</span></span> <span class="line"><span style="color:#222222"> candidate.</span><span style="color:#6200EE">interview</span><span style="color:#222222">();</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>To process the values obtained from the iterable, you can also use a <a href="/language/patterns">pattern</a> in a <code>for-in</code> loop:</p> <?code-excerpt "language/lib/control_flow/loops.dart (collection-for-pattern)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">for</span><span style="color:#222222"> (</span><span style="color:#D43324">final</span><span style="color:#0468D7"> Candidate</span><span style="color:#222222">(:name, :yearsExperience) </span><span style="color:#D43324">in</span><span style="color:#222222"> candidates) {</span></span> <span class="line"><span style="color:#6200EE"> print</span><span style="color:#222222">(</span><span style="color:#11796D">'</span><span style="color:#11796D">$</span><span style="color:#222222">name</span><span style="color:#11796D"> has </span><span style="color:#11796D">$</span><span style="color:#222222">yearsExperience</span><span style="color:#11796D"> of experience.'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><aside class="alert alert-success"><div class="alert-header"><span class="material-symbols" aria-hidden="true">lightbulb</span> <span>Tip</span></div><div class="alert-content"><p>To practice using <code>for-in</code>, follow the <a href="/libraries/collections/iterables">Iterable collections tutorial</a>.</p></div></aside><p>Iterable classes also have a <a href="https://api.dart.dev/dart-core/Iterable/forEach.html">forEach()</a> method as another option:</p> <?code-excerpt "language/test/control_flow/loops_test.dart (for-each)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">var</span><span style="color:#222222"> collection = [</span><span style="color:#11796D">1</span><span style="color:#222222">, </span><span style="color:#11796D">2</span><span style="color:#222222">, </span><span style="color:#11796D">3</span><span style="color:#222222">];</span></span> <span class="line"><span style="color:#222222">collection.</span><span style="color:#6200EE">forEach</span><span style="color:#222222">(print); </span><span style="color:#6E6E70">// 1 2 3</span></span></code></pre></div></div><div class="header-wrapper"><h2 id="while-and-do-while">While and do-while</h2><a class="heading-link" href="#while-and-do-while" aria-label="Link to 'While and do-while' section">#</a></div><p>A <code>while</code> loop evaluates the condition before the loop:</p> <?code-excerpt "language/lib/control_flow/loops.dart (while)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">while</span><span style="color:#222222"> (!</span><span style="color:#6200EE">isDone</span><span style="color:#222222">()) {</span></span> <span class="line"><span style="color:#6200EE"> doSomething</span><span style="color:#222222">();</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>A <code>do</code>-<code>while</code> loop evaluates the condition <em>after</em> the loop:</p> <?code-excerpt "language/lib/control_flow/loops.dart (do-while)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">do</span><span style="color:#222222"> {</span></span> <span class="line"><span style="color:#6200EE"> printLine</span><span style="color:#222222">();</span></span> <span class="line"><span style="color:#222222">} </span><span style="color:#D43324">while</span><span style="color:#222222"> (!</span><span style="color:#6200EE">atEndOfPage</span><span style="color:#222222">());</span></span></code></pre></div></div><div class="header-wrapper"><h2 id="break-and-continue">Break and continue</h2><a class="heading-link" href="#break-and-continue" aria-label="Link to 'Break and continue' section">#</a></div><p>Use <code>break</code> to stop looping:</p> <?code-excerpt "language/lib/control_flow/loops.dart (while-break)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">while</span><span style="color:#222222"> (</span><span style="color:#11796D">true</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#D43324"> if</span><span style="color:#222222"> (</span><span style="color:#6200EE">shutDownRequested</span><span style="color:#222222">()) </span><span style="color:#D43324">break</span><span style="color:#222222">;</span></span> <span class="line"><span style="color:#6200EE"> processIncomingRequests</span><span style="color:#222222">();</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>Use <code>continue</code> to skip to the next loop iteration:</p> <?code-excerpt "language/lib/control_flow/loops.dart (for-continue)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">for</span><span style="color:#222222"> (</span><span style="color:#0468D7">int</span><span style="color:#222222"> i = </span><span style="color:#11796D">0</span><span style="color:#222222">; i < candidates.length; i++) {</span></span> <span class="line"><span style="color:#D43324"> var</span><span style="color:#222222"> candidate = candidates[i];</span></span> <span class="line"><span style="color:#D43324"> if</span><span style="color:#222222"> (candidate.yearsExperience < </span><span style="color:#11796D">5</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#D43324"> continue</span><span style="color:#222222">;</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#222222"> candidate.</span><span style="color:#6200EE">interview</span><span style="color:#222222">();</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>If you're using an <a href="https://api.dart.dev/dart-core/Iterable-class.html"><code>Iterable</code></a> such as a list or set, how you write the previous example might differ:</p> <?code-excerpt "language/lib/control_flow/loops.dart (where)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#222222">candidates</span></span> <span class="line"><span style="color:#222222"> .</span><span style="color:#6200EE">where</span><span style="color:#222222">((c) => c.yearsExperience >= </span><span style="color:#11796D">5</span><span style="color:#222222">)</span></span> <span class="line"><span style="color:#222222"> .</span><span style="color:#6200EE">forEach</span><span style="color:#222222">((c) => c.</span><span style="color:#6200EE">interview</span><span style="color:#222222">());</span></span></code></pre></div></div><div class="header-wrapper"><h2 id="labels">Labels</h2><a class="heading-link" href="#labels" aria-label="Link to 'Labels' section">#</a></div><p>A label is an identifier followed by a colon (<code>labelName:</code>) that you can place before a statement to create a <em>labeled statement</em>. Loops and switch cases are often used as labeled statements. A labeled statement can be referenced later in a <code>break</code> or <code>continue</code> statement as follows:</p><ul><li><p><code>break labelName;</code> Terminates the execution of the labeled statement. This is useful for breaking out of a specific outer loop when you're within a nested loop.</p></li><li><p><code>continue labelName;</code> Skips the rest of the current iteration of the labeled statement loop and continues with the next iteration.</p></li></ul><p>Labels are used to manage control flow. They are often used with loops and switch cases and allow you to specify which statement to break out of or continue, rather than affecting the innermost loop by default.</p><div class="header-wrapper"><h3 class="no_toc" id="labels-in-for-loop-using-break">Labels in for loop using <code>break</code></h3><a class="heading-link" href="#labels-in-for-loop-using-break" aria-label="Link to 'Labels in for loop using break' section">#</a></div><p>The following code demonstrates the usage of a label called <code>outerLoop</code> in a <code>for</code> loop with a <code>break</code> statement:</p> <?code-excerpt "language/lib/control_flow/loops.dart (label-for-loop-break)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#222222">outerLoop:</span></span> <span class="line"><span style="color:#D43324">for</span><span style="color:#222222"> (</span><span style="color:#D43324">var</span><span style="color:#222222"> i = </span><span style="color:#11796D">1</span><span style="color:#222222">; i <= </span><span style="color:#11796D">3</span><span style="color:#222222">; i++) {</span></span> <span class="line"><span style="color:#D43324"> for</span><span style="color:#222222"> (</span><span style="color:#D43324">var</span><span style="color:#222222"> j = </span><span style="color:#11796D">1</span><span style="color:#222222">; j <= </span><span style="color:#11796D">3</span><span style="color:#222222">; j++) {</span></span> <span class="line"><span style="color:#6200EE"> print</span><span style="color:#222222">(</span><span style="color:#11796D">'i = </span><span style="color:#11796D">$</span><span style="color:#222222">i</span><span style="color:#11796D">, j = </span><span style="color:#11796D">$</span><span style="color:#222222">j</span><span style="color:#11796D">'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#D43324"> if</span><span style="color:#222222"> (i == </span><span style="color:#11796D">2</span><span style="color:#222222"> && j == </span><span style="color:#11796D">2</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#D43324"> break</span><span style="color:#222222"> outerLoop;</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#222222">}</span></span> <span class="line"><span style="color:#6200EE">print</span><span style="color:#222222">(</span><span style="color:#11796D">'outerLoop exited'</span><span style="color:#222222">);</span></span></code></pre></div></div><p>In the previous example, when <code>i == 2</code> and <code>j == 2</code>, the <code>break outerLoop;</code> statement stops both inner and outer loops. As a result, the output is:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>i = 1, j = 1</span></span> <span class="line"><span>i = 1, j = 2</span></span> <span class="line"><span>i = 1, j = 3</span></span> <span class="line"><span>i = 2, j = 1</span></span> <span class="line"><span>i = 2, j = 2</span></span> <span class="line"><span>outerLoop exited</span></span></code></pre></div></div><div class="header-wrapper"><h3 class="no_toc" id="labels-in-for-loop-using-continue">Labels in for loop using <code>continue</code></h3><a class="heading-link" href="#labels-in-for-loop-using-continue" aria-label="Link to 'Labels in for loop using continue' section">#</a></div><p>The following code demonstrates the use of a label called <code>outerLoop</code> in a <code>for</code> loop with a <code>continue</code> statement:</p> <?code-excerpt "language/lib/control_flow/loops.dart (label-for-loop-continue)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#222222">outerLoop:</span></span> <span class="line"><span style="color:#D43324">for</span><span style="color:#222222"> (</span><span style="color:#D43324">var</span><span style="color:#222222"> i = </span><span style="color:#11796D">1</span><span style="color:#222222">; i <= </span><span style="color:#11796D">3</span><span style="color:#222222">; i++) {</span></span> <span class="line"><span style="color:#D43324"> for</span><span style="color:#222222"> (</span><span style="color:#D43324">var</span><span style="color:#222222"> j = </span><span style="color:#11796D">1</span><span style="color:#222222">; j <= </span><span style="color:#11796D">3</span><span style="color:#222222">; j++) {</span></span> <span class="line"><span style="color:#D43324"> if</span><span style="color:#222222"> (i == </span><span style="color:#11796D">2</span><span style="color:#222222"> && j == </span><span style="color:#11796D">2</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#D43324"> continue</span><span style="color:#222222"> outerLoop;</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#6200EE"> print</span><span style="color:#222222">(</span><span style="color:#11796D">'i = </span><span style="color:#11796D">$</span><span style="color:#222222">i</span><span style="color:#11796D">, j = </span><span style="color:#11796D">$</span><span style="color:#222222">j</span><span style="color:#11796D">'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>In the previous example, when <code>i == 2</code> and <code>j == 2</code>, <code>continue outerLoop;</code> skips the rest of the iterations for <code>i = 2</code> and moves to <code>i = 3</code>. As a result, the output is:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>i = 1, j = 1</span></span> <span class="line"><span>i = 1, j = 2</span></span> <span class="line"><span>i = 1, j = 3</span></span> <span class="line"><span>i = 2, j = 1</span></span> <span class="line"><span>i = 3, j = 1</span></span> <span class="line"><span>i = 3, j = 2</span></span> <span class="line"><span>i = 3, j = 3</span></span></code></pre></div></div><div class="header-wrapper"><h3 class="no_toc" id="labels-in-while-loop-using-break">Labels in while loop using <code>break</code></h3><a class="heading-link" href="#labels-in-while-loop-using-break" aria-label="Link to 'Labels in while loop using break' section">#</a></div><p>The following code demonstrates the use of a label called <code>outerLoop</code> in a <code>while</code> loop with a <code>break</code> statement:</p> <?code-excerpt "language/lib/control_flow/loops.dart (label-while-loop-break)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">var</span><span style="color:#222222"> i = </span><span style="color:#11796D">1</span><span style="color:#222222">;</span></span> <span class="line"></span> <span class="line"><span style="color:#222222">outerLoop:</span></span> <span class="line"><span style="color:#D43324">while</span><span style="color:#222222"> (i <= </span><span style="color:#11796D">3</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#D43324"> var</span><span style="color:#222222"> j = </span><span style="color:#11796D">1</span><span style="color:#222222">;</span></span> <span class="line"><span style="color:#D43324"> while</span><span style="color:#222222"> (j <= </span><span style="color:#11796D">3</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#6200EE"> print</span><span style="color:#222222">(</span><span style="color:#11796D">'i = </span><span style="color:#11796D">$</span><span style="color:#222222">i</span><span style="color:#11796D">, j = </span><span style="color:#11796D">$</span><span style="color:#222222">j</span><span style="color:#11796D">'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#D43324"> if</span><span style="color:#222222"> (i == </span><span style="color:#11796D">2</span><span style="color:#222222"> && j == </span><span style="color:#11796D">2</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#D43324"> break</span><span style="color:#222222"> outerLoop;</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#222222"> j++;</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#222222"> i++;</span></span> <span class="line"><span style="color:#222222">}</span></span> <span class="line"><span style="color:#6200EE">print</span><span style="color:#222222">(</span><span style="color:#11796D">'outerLoop exited'</span><span style="color:#222222">);</span></span></code></pre></div></div><p>In the previous example, the program breaks out of both inner and outer <code>while</code> loops when <code>i == 2</code> and <code>j == 2</code>. As a result, the output is:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>i = 1, j = 1</span></span> <span class="line"><span>i = 1, j = 2</span></span> <span class="line"><span>i = 1, j = 3</span></span> <span class="line"><span>i = 2, j = 1</span></span> <span class="line"><span>i = 2, j = 2</span></span> <span class="line"><span>outerLoop exited</span></span></code></pre></div></div><div class="header-wrapper"><h3 class="no_toc" id="labels-in-while-loop-using-continue">Labels in while loop using <code>continue</code></h3><a class="heading-link" href="#labels-in-while-loop-using-continue" aria-label="Link to 'Labels in while loop using continue' section">#</a></div><p>The following code demonstrates the use of a label called <code>outerLoop</code> in a <code>while</code> loop with a <code>continue</code> statement:</p> <?code-excerpt "language/lib/control_flow/loops.dart (label-while-loop-continue)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">var</span><span style="color:#222222"> i = </span><span style="color:#11796D">1</span><span style="color:#222222">;</span></span> <span class="line"></span> <span class="line"><span style="color:#222222">outerLoop:</span></span> <span class="line"><span style="color:#D43324">while</span><span style="color:#222222"> (i <= </span><span style="color:#11796D">3</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#D43324"> var</span><span style="color:#222222"> j = </span><span style="color:#11796D">1</span><span style="color:#222222">;</span></span> <span class="line"><span style="color:#D43324"> while</span><span style="color:#222222"> (j <= </span><span style="color:#11796D">3</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#D43324"> if</span><span style="color:#222222"> (i == </span><span style="color:#11796D">2</span><span style="color:#222222"> && j == </span><span style="color:#11796D">2</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#222222"> i++;</span></span> <span class="line"><span style="color:#D43324"> continue</span><span style="color:#222222"> outerLoop;</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#6200EE"> print</span><span style="color:#222222">(</span><span style="color:#11796D">'i = </span><span style="color:#11796D">$</span><span style="color:#222222">i</span><span style="color:#11796D">, j = </span><span style="color:#11796D">$</span><span style="color:#222222">j</span><span style="color:#11796D">'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#222222"> j++;</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#222222"> i++;</span></span> <span class="line"><span style="color:#222222">}</span></span></code></pre></div></div><p>In the previous example, the iteration for <code>i = 2</code> and <code>j = 2</code> is skipped and the loop moves directly to <code>i = 3</code>. As a result, the output is:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>i = 1, j = 1</span></span> <span class="line"><span>i = 1, j = 2</span></span> <span class="line"><span>i = 1, j = 3</span></span> <span class="line"><span>i = 2, j = 1</span></span> <span class="line"><span>i = 3, j = 1</span></span> <span class="line"><span>i = 3, j = 2</span></span> <span class="line"><span>i = 3, j = 3</span></span></code></pre></div></div><div class="header-wrapper"><h3 class="no_toc" id="labels-in-do-while-loop-using-break">Labels in do-while loop using <code>break</code></h3><a class="heading-link" href="#labels-in-do-while-loop-using-break" aria-label="Link to 'Labels in do-while loop using break' section">#</a></div><p>The following code demonstrates the use of a label called <code>outerLoop</code> in a <code>do while</code> loop with a <code>break</code> statement:</p> <?code-excerpt "language/lib/control_flow/loops.dart (label-do-while-loop-break)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">var</span><span style="color:#222222"> i = </span><span style="color:#11796D">1</span><span style="color:#222222">;</span></span> <span class="line"></span> <span class="line"><span style="color:#222222">outerLoop:</span></span> <span class="line"><span style="color:#D43324">do</span><span style="color:#222222"> {</span></span> <span class="line"><span style="color:#D43324"> var</span><span style="color:#222222"> j = </span><span style="color:#11796D">1</span><span style="color:#222222">;</span></span> <span class="line"><span style="color:#D43324"> do</span><span style="color:#222222"> {</span></span> <span class="line"><span style="color:#6200EE"> print</span><span style="color:#222222">(</span><span style="color:#11796D">'i = </span><span style="color:#11796D">$</span><span style="color:#222222">i</span><span style="color:#11796D">, j = </span><span style="color:#11796D">$</span><span style="color:#222222">j</span><span style="color:#11796D">'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#D43324"> if</span><span style="color:#222222"> (i == </span><span style="color:#11796D">2</span><span style="color:#222222"> && j == </span><span style="color:#11796D">2</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#D43324"> break</span><span style="color:#222222"> outerLoop;</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#222222"> j++;</span></span> <span class="line"><span style="color:#222222"> } </span><span style="color:#D43324">while</span><span style="color:#222222"> (j <= </span><span style="color:#11796D">3</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#222222"> i++;</span></span> <span class="line"><span style="color:#222222">} </span><span style="color:#D43324">while</span><span style="color:#222222"> (i <= </span><span style="color:#11796D">3</span><span style="color:#222222">);</span></span> <span class="line"></span> <span class="line"><span style="color:#6200EE">print</span><span style="color:#222222">(</span><span style="color:#11796D">'outerLoop exited'</span><span style="color:#222222">);</span></span></code></pre></div></div><p>In the previous example, the program breaks out of both inner and outer loops when <code>i == 2</code> and <code>j == 2</code>. As a result, the output is:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>i = 1, j = 1</span></span> <span class="line"><span>i = 1, j = 2</span></span> <span class="line"><span>i = 1, j = 3</span></span> <span class="line"><span>i = 2, j = 1</span></span> <span class="line"><span>i = 2, j = 2</span></span> <span class="line"><span>outerLoop exited</span></span></code></pre></div></div><div class="header-wrapper"><h3 class="no_toc" id="labels-in-do-while-loop-using-continue">Labels in do-while loop using <code>continue</code></h3><a class="heading-link" href="#labels-in-do-while-loop-using-continue" aria-label="Link to 'Labels in do-while loop using continue' section">#</a></div><p>The following code demonstrates the use of a label called <code>outerLoop</code> in a <code>do while</code> loop with a <code>continue</code> statement:</p> <?code-excerpt "language/lib/control_flow/loops.dart (label-do-while-loop-continue)"?> <div class="code-block-wrapper language-dart"><div class="code-block-body"><span class="code-block-language" title="Language dart">dart</span><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span style="color:#D43324">var</span><span style="color:#222222"> i = </span><span style="color:#11796D">1</span><span style="color:#222222">;</span></span> <span class="line"></span> <span class="line"><span style="color:#222222">outerLoop:</span></span> <span class="line"><span style="color:#D43324">do</span><span style="color:#222222"> {</span></span> <span class="line"><span style="color:#D43324"> var</span><span style="color:#222222"> j = </span><span style="color:#11796D">1</span><span style="color:#222222">;</span></span> <span class="line"><span style="color:#D43324"> do</span><span style="color:#222222"> {</span></span> <span class="line"><span style="color:#D43324"> if</span><span style="color:#222222"> (i == </span><span style="color:#11796D">2</span><span style="color:#222222"> && j == </span><span style="color:#11796D">2</span><span style="color:#222222">) {</span></span> <span class="line"><span style="color:#222222"> i++;</span></span> <span class="line"><span style="color:#D43324"> continue</span><span style="color:#222222"> outerLoop;</span></span> <span class="line"><span style="color:#222222"> }</span></span> <span class="line"><span style="color:#6200EE"> print</span><span style="color:#222222">(</span><span style="color:#11796D">'i = </span><span style="color:#11796D">$</span><span style="color:#222222">i</span><span style="color:#11796D">, j = </span><span style="color:#11796D">$</span><span style="color:#222222">j</span><span style="color:#11796D">'</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#222222"> j++;</span></span> <span class="line"><span style="color:#222222"> } </span><span style="color:#D43324">while</span><span style="color:#222222"> (j <= </span><span style="color:#11796D">3</span><span style="color:#222222">);</span></span> <span class="line"><span style="color:#222222"> i++;</span></span> <span class="line"><span style="color:#222222">} </span><span style="color:#D43324">while</span><span style="color:#222222"> (i <= </span><span style="color:#11796D">3</span><span style="color:#222222">);</span></span></code></pre></div></div><p>In the previous example, the loop skips <code>i = 2</code> and <code>j = 2</code> and moves directly to <code>i = 3</code>. As a result, the output is:</p><div class="code-block-wrapper language-plaintext"><div class="code-block-body"><pre class="shiki dash-light" tabindex="0"><code><span class="line"><span>i = 1, j = 1</span></span> <span class="line"><span>i = 1, j = 2</span></span> <span class="line"><span>i = 1, j = 3</span></span> <span class="line"><span>i = 2, j = 1</span></span> <span class="line"><span>i = 3, j = 1</span></span> <span class="line"><span>i = 3, j = 2</span></span> <span class="line"><span>i = 3, j = 3</span></span></code></pre></div></div><nav id="prev-next"><ul><li class="previous"><a href="/language/functions">&lang;  Functions</a></li><li class="next"><a href="/language/branches">Branches  &rang;</a></li></ul></nav><p id="page-github-links"><span>Unless stated otherwise, the documentation on this site reflects Dart 3.7.2. Page last updated on 2025-03-19.</span> <a href="https://github.com/dart-lang/site-www/tree/main/src/content/language/loops.md" target="_blank" rel="noopener">View source</a> <span>or </span><a href="https://github.com/dart-lang/site-www/issues/new?template=1_page_issue.yml&page-url=https://dart.dev/language/loops/&page-source=https://github.com/dart-lang/site-www/tree/main/src/content/language/loops.md" title="Report an issue with this page" target="_blank" rel="noopener">report an issue</a>.</p></div></article></main></div><footer id="page-footer"><div class="footer-section footer-main"><a href="/" class="brand" title="Dart"><img src="/assets/img/logo/logo-white-text.svg" alt="Dart" width="164"></a><div class="footer-social-links"><a href="https://medium.com/dartlang" target="_blank" rel="noopener" title="Dart's Medium publication"><svg><use href="/assets/img/social/medium.svg#medium"></use></svg> </a><a href="https://github.com/dart-lang" target="_blank" rel="noopener" title="Dart's GitHub organization"><svg><use href="/assets/img/social/github.svg#github"></use></svg> </a><a href="https://bsky.app/profile/dart.dev" target="_blank" rel="noopener" title="Dart's Bluesky profile"><svg><use href="/assets/img/social/bluesky.svg#bluesky"></use></svg> </a><a href="https://twitter.com/dart_lang" target="_blank" rel="noopener" title="Dart's X (Twitter) profile"><svg><use href="/assets/img/social/x.svg#x"></use></svg></a></div></div><div class="footer-section footer-tray"><div class="footer-licenses">Except as otherwise noted, this site is licensed under a <a href="https://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</a>, and code samples are licensed under the <a href="https://opensource.org/licenses/BSD-3-Clause">3-Clause BSD License</a>.</div><div class="footer-utility-links"><ul><li><a href="/terms" title="Terms of use">Terms</a></li><li><a href="https://policies.google.com/privacy" target="_blank" rel="noopener" title="Privacy policy">Privacy</a></li><li><a href="/security" title="Security philosophy and practices">Security</a></li></ul></div></div></footer></div></body></html>