162 lines
7.8 KiB
HTML
162 lines
7.8 KiB
HTML
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<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<meta name="generator" content="rustdoc">
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<meta name="description" content="API documentation for the Rust `random` fn in crate `rand`.">
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<meta name="keywords" content="rust, rustlang, rust-lang, random">
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<title>rand::random - Rust</title>
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<link rel="stylesheet" type="text/css" href="../normalize.css">
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<link rel="stylesheet" type="text/css" href="../rustdoc.css" id="mainThemeStyle">
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<script src="../storage.js"></script>
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<link rel="shortcut icon" href="https://www.rust-lang.org/favicon.ico">
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</head>
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<body class="rustdoc fn">
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<!--[if lte IE 8]>
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<div class="warning">
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This old browser is unsupported and will most likely display funky
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things.
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</div>
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<![endif]-->
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<nav class="sidebar">
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<div class="sidebar-menu">☰</div>
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<a href='../rand/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk.png' alt='logo' width='100'></a>
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<p class='location'><a href='index.html'>rand</a></p><script>window.sidebarCurrent = {name: 'random', ty: 'fn', relpath: ''};</script><script defer src="sidebar-items.js"></script>
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</nav>
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<script src="../theme.js"></script>
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<nav class="sub">
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<form class="search-form js-only">
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<div class="search-container">
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<input class="search-input" name="search"
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autocomplete="off"
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placeholder="Click or press ‘S’ to search, ‘?’ for more options…"
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type="search">
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</div>
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</form>
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</nav>
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<section id='main' class="content">
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<h1 class='fqn'><span class='in-band'>Function <a href='index.html'>rand</a>::<wbr><a class="fn" href=''>random</a></span><span class='out-of-band'><span id='render-detail'>
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<a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">
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[<span class='inner'>−</span>]
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</a>
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</span><a class='srclink' href='../src/rand/lib.rs.html#955-957' title='goto source code'>[src]</a></span></h1>
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<pre class='rust fn'>pub fn random<T>() -> T <span class="where fmt-newline">where<br> T: <a class="trait" href="../rand/trait.Rand.html" title="trait rand::Rand">Rand</a>, </span></pre><div class='docblock'><p>Generates a random value using the thread-local random number generator.</p>
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<p><code>random()</code> can generate various types of random things, and so may require
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type hinting to generate the specific type you want.</p>
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<p>This function uses the thread local random number generator. This means
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that if you're calling <code>random()</code> in a loop, caching the generator can
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increase performance. An example is shown below.</p>
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<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
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<pre class="rust rust-example-rendered">
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<span class="kw">let</span> <span class="ident">x</span> <span class="op">=</span> <span class="ident">rand</span>::<span class="ident">random</span>::<span class="op"><</span><span class="ident">u8</span><span class="op">></span>();
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<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{}"</span>, <span class="ident">x</span>);
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<span class="kw">let</span> <span class="ident">y</span> <span class="op">=</span> <span class="ident">rand</span>::<span class="ident">random</span>::<span class="op"><</span><span class="ident">f64</span><span class="op">></span>();
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<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{}"</span>, <span class="ident">y</span>);
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<span class="kw">if</span> <span class="ident">rand</span>::<span class="ident">random</span>() { <span class="comment">// generates a boolean</span>
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<span class="macro">println</span><span class="macro">!</span>(<span class="string">"Better lucky than good!"</span>);
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}</pre>
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<p>Caching the thread local random number generator:</p>
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<pre class="rust rust-example-rendered">
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<span class="kw">use</span> <span class="ident">rand</span>::<span class="ident">Rng</span>;
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<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">v</span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>];
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<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="ident">v</span>.<span class="ident">iter_mut</span>() {
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<span class="kw-2">*</span><span class="ident">x</span> <span class="op">=</span> <span class="ident">rand</span>::<span class="ident">random</span>()
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}
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<span class="comment">// can be made faster by caching thread_rng</span>
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<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident">rand</span>::<span class="ident">thread_rng</span>();
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<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="ident">v</span>.<span class="ident">iter_mut</span>() {
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<span class="kw-2">*</span><span class="ident">x</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">gen</span>();
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}</pre>
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</div></section>
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<section id='search' class="content hidden"></section>
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<section class="footer"></section>
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<aside id="help" class="hidden">
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<div>
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<h1 class="hidden">Help</h1>
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<div class="shortcuts">
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<h2>Keyboard Shortcuts</h2>
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<dl>
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<dt><kbd>?</kbd></dt>
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<dd>Show this help dialog</dd>
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<dt><kbd>S</kbd></dt>
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<dd>Focus the search field</dd>
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<dt><kbd>↑</kbd></dt>
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<dd>Move up in search results</dd>
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<dd>Move down in search results</dd>
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<dd>Switch tab</dd>
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<dd>Go to active search result</dd>
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<dd>Expand all sections</dd>
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<dt><kbd>-</kbd></dt>
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<dd>Collapse all sections</dd>
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</dl>
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</div>
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<div class="infos">
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<h2>Search Tricks</h2>
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<p>
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Prefix searches with a type followed by a colon (e.g.
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<code>fn:</code>) to restrict the search to a given type.
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</p>
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<p>
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Accepted types are: <code>fn</code>, <code>mod</code>,
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<code>struct</code>, <code>enum</code>,
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<code>trait</code>, <code>type</code>, <code>macro</code>,
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and <code>const</code>.
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</p>
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<p>
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Search functions by type signature (e.g.
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<code>vec -> usize</code> or <code>* -> vec</code>)
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</p>
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</div>
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</div>
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</aside>
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<script>
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window.rootPath = "../";
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window.currentCrate = "rand";
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</script>
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<script src="../main.js"></script>
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</body>
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