|
|
<!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="Creates a parallel iterator that produces an element exactly once."><title>once in rayon::iter - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/SourceSerif4-Regular-46f98efaafac5295.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/FiraSans-Regular-018c141bf0843ffd.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/FiraSans-Medium-8f9a781e4970d388.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2"><link rel="stylesheet" href="../../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../../static.files/rustdoc-ac92e1bbe349e143.css"><meta name="rustdoc-vars" data-root-path="../../" data-static-root-path="../../static.files/" data-current-crate="rayon" data-themes="" data-resource-suffix="" data-rustdoc-version="1.76.0 (07dca489a 2024-02-04)" data-channel="1.76.0" data-search-js="search-2b6ce74ff89ae146.js" data-settings-js="settings-4313503d2e1961c2.js" ><script src="../../static.files/storage-f2adc0d6ca4d09fb.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../static.files/main-305769736d49e732.js"></script><noscript><link rel="stylesheet" href="../../static.files/noscript-feafe1bb7466e4bd.css"></noscript><link rel="alternate icon" type="image/png" href="../../static.files/favicon-16x16-8b506e7a72182f1c.png"><link rel="alternate icon" type="image/png" href="../../static.files/favicon-32x32-422f7d1d52889060.png"><link rel="icon" type="image/svg+xml" href="../../static.files/favicon-2c020d218678b618.svg"></head><body class="rustdoc fn"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">☰</button></nav><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../../rayon/index.html">rayon</a><span class="version">1.10.0</span></h2></div><div class="sidebar-elems"><h2><a href="index.html">In rayon::iter</a></h2></div></nav><div class="sidebar-resizer"></div>
|
|
|
<main><div class="width-limiter"><nav class="sub"><form class="search-form"><span></span><div id="sidebar-button" tabindex="-1"><a href="../../rayon/all.html" title="show sidebar"></a></div><input class="search-input" name="search" aria-label="Run search in the documentation" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" tabindex="-1"><a href="../../help.html" title="help">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1>Function <a href="../index.html">rayon</a>::<wbr><a href="index.html">iter</a>::<wbr><a class="fn" href="#">once</a><button id="copy-path" title="Copy item path to clipboard"><img src="../../static.files/clipboard-7571035ce49a181d.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="src" href="../../src/rayon/iter/once.rs.html#24-26">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>−</span>]</button></span></div><pre class="rust item-decl"><code>pub fn once<T: <a class="trait" href="https://doc.rust-lang.org/1.76.0/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a>>(item: T) -> <a class="struct" href="struct.Once.html" title="struct rayon::iter::Once">Once</a><T></code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Creates a parallel iterator that produces an element exactly once.</p>
|
|
|
<p>This admits no parallelism on its own, but it could be chained to existing
|
|
|
parallel iterators to extend their contents, or otherwise used for any code
|
|
|
that deals with generic parallel iterators.</p>
|
|
|
<h2 id="examples"><a href="#examples">Examples</a></h2>
|
|
|
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>;
|
|
|
<span class="kw">use </span>rayon::iter::once;
|
|
|
|
|
|
<span class="kw">let </span>pi = (<span class="number">0</span>..<span class="number">1234</span>).into_par_iter()
|
|
|
.chain(once(-<span class="number">1</span>))
|
|
|
.chain(<span class="number">1234</span>..<span class="number">10_000</span>);
|
|
|
|
|
|
<span class="macro">assert_eq!</span>(pi.clone().count(), <span class="number">10_001</span>);
|
|
|
<span class="macro">assert_eq!</span>(pi.clone().filter(|<span class="kw-2">&</span>x| x < <span class="number">0</span>).count(), <span class="number">1</span>);
|
|
|
<span class="macro">assert_eq!</span>(pi.position_any(|x| x < <span class="number">0</span>), <span class="prelude-val">Some</span>(<span class="number">1234</span>));</code></pre></div>
|
|
|
</div></details></section></div></main></body></html> |