<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta name="generator" content="rustdoc"> <meta name="description" content="API documentation for the Rust `repeat` fn in crate `core`."> <meta name="keywords" content="rust, rustlang, rust-lang, repeat"> <title>core::iter::repeat - Rust</title> <link rel="stylesheet" type="text/css" href="../../normalize.css"> <link rel="stylesheet" type="text/css" href="../../rustdoc.css"> <link rel="stylesheet" type="text/css" href="../../main.css"> <link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"> </head> <body class="rustdoc fn"> <!--[if lte IE 8]> <div class="warning"> This old browser is unsupported and will most likely display funky things. </div> <![endif]--> <nav class="sidebar"> <a href='../../core/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a> <p class='location'><a href='../index.html'>core</a>::<wbr><a href='index.html'>iter</a></p><script>window.sidebarCurrent = {name: 'repeat', ty: 'fn', relpath: ''};</script><script defer src="sidebar-items.js"></script> </nav> <nav class="sub"> <form class="search-form js-only"> <div class="search-container"> <input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"> </div> </form> </nav> <section id='main' class="content"> <h1 class='fqn'><span class='in-band'>Function <a href='../index.html'>core</a>::<wbr><a href='index.html'>iter</a>::<wbr><a class="fn" href=''>repeat</a></span><span class='out-of-band'><span class='since' title='Stable since Rust version 1.0.0'>1.0.0</span><span id='render-detail'> <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs"> [<span class='inner'>−</span>] </a> </span><a class='srclink' href='../../src/core/iter/sources.rs.html#95-97' title='goto source code'>[src]</a></span></h1> <pre class='rust fn'>pub fn repeat<T: <a class="trait" href="../../core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>>(elt: T) -> <a class="struct" href="../../core/iter/struct.Repeat.html" title="struct core::iter::Repeat">Repeat</a><T></pre><div class='docblock'><p>Creates a new iterator that endlessly repeats a single element.</p> <p>The <code>repeat()</code> function repeats a single value over and over and over and over and over and 🔁.</p> <p>Infinite iterators like <code>repeat()</code> are often used with adapters like <a href="trait.Iterator.html#method.take"><code>take</code></a>, in order to make them finite.</p> <h1 id='examples' class='section-header'><a href='#examples'>Examples</a></h1> <p>Basic usage:</p> <pre class="rust rust-example-rendered"> <span class="kw">use</span> <span class="ident">std</span>::<span class="ident">iter</span>; <span class="comment">// the number four 4ever:</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">fours</span> <span class="op">=</span> <span class="ident">iter</span>::<span class="ident">repeat</span>(<span class="number">4</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">fours</span>.<span class="ident">next</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">fours</span>.<span class="ident">next</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">fours</span>.<span class="ident">next</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">fours</span>.<span class="ident">next</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">fours</span>.<span class="ident">next</span>()); <span class="comment">// yup, still four</span> <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">fours</span>.<span class="ident">next</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=fn%20main()%20%7B%0Ause%20std%3A%3Aiter%3B%0A%0A%2F%2F%20the%20number%20four%204ever%3A%0Alet%20mut%20fours%20%3D%20iter%3A%3Arepeat(4)%3B%0A%0Aassert_eq!(Some(4)%2C%20fours.next())%3B%0Aassert_eq!(Some(4)%2C%20fours.next())%3B%0Aassert_eq!(Some(4)%2C%20fours.next())%3B%0Aassert_eq!(Some(4)%2C%20fours.next())%3B%0Aassert_eq!(Some(4)%2C%20fours.next())%3B%0A%0A%2F%2F%20yup%2C%20still%20four%0Aassert_eq!(Some(4)%2C%20fours.next())%3B%0A%7D">Run</a></pre> <p>Going finite with <a href="trait.Iterator.html#method.take"><code>take</code></a>:</p> <pre class="rust rust-example-rendered"> <span class="kw">use</span> <span class="ident">std</span>::<span class="ident">iter</span>; <span class="comment">// that last example was too many fours. Let's only have four fours.</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">four_fours</span> <span class="op">=</span> <span class="ident">iter</span>::<span class="ident">repeat</span>(<span class="number">4</span>).<span class="ident">take</span>(<span class="number">4</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">four_fours</span>.<span class="ident">next</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">four_fours</span>.<span class="ident">next</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">four_fours</span>.<span class="ident">next</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">Some</span>(<span class="number">4</span>), <span class="ident">four_fours</span>.<span class="ident">next</span>()); <span class="comment">// ... and now we're done</span> <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="prelude-val">None</span>, <span class="ident">four_fours</span>.<span class="ident">next</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=fn%20main()%20%7B%0Ause%20std%3A%3Aiter%3B%0A%0A%2F%2F%20that%20last%20example%20was%20too%20many%20fours.%20Let's%20only%20have%20four%20fours.%0Alet%20mut%20four_fours%20%3D%20iter%3A%3Arepeat(4).take(4)%3B%0A%0Aassert_eq!(Some(4)%2C%20four_fours.next())%3B%0Aassert_eq!(Some(4)%2C%20four_fours.next())%3B%0Aassert_eq!(Some(4)%2C%20four_fours.next())%3B%0Aassert_eq!(Some(4)%2C%20four_fours.next())%3B%0A%0A%2F%2F%20...%20and%20now%20we're%20done%0Aassert_eq!(None%2C%20four_fours.next())%3B%0A%7D">Run</a></pre> </div></section> <section id='search' class="content hidden"></section> <section class="footer"></section> <aside id="help" class="hidden"> <div> <h1 class="hidden">Help</h1> <div class="shortcuts"> <h2>Keyboard Shortcuts</h2> <dl> <dt>?</dt> <dd>Show this help dialog</dd> <dt>S</dt> <dd>Focus the search field</dd> <dt>⇤</dt> <dd>Move up in search results</dd> <dt>⇥</dt> <dd>Move down in search results</dd> <dt>⏎</dt> <dd>Go to active search result</dd> <dt>+</dt> <dd>Collapse/expand all sections</dd> </dl> </div> <div class="infos"> <h2>Search Tricks</h2> <p> Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type. </p> <p> Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>. </p> <p> Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>) </p> </div> </div> </aside> <script> window.rootPath = "../../"; window.currentCrate = "core"; </script> <script src="../../main.js"></script> <script defer src="../../search-index.js"></script> </body> </html>