| <!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="Utilities for random number generation"><meta name="keywords" content="rust, rustlang, rust-lang, rand"><title>rand - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" type="text/css" href="../normalize.css"><link rel="stylesheet" type="text/css" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../ayu.css" disabled><link rel="stylesheet" type="text/css" href="../dark.css" disabled><link rel="stylesheet" type="text/css" href="../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../storage.js"></script><script src="../crates.js"></script><script defer src="../main.js"></script> |
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| </a><h2 class="location">Crate rand</h2><div class="block version"><div class="narrow-helper"></div><p>Version 0.8.5</p></div><div class="sidebar-elems"><a id="all-types" href="all.html"><p>See all rand's items</p></a><div class="block items"><ul><li><a href="#modules">Modules</a></li><li><a href="#structs">Structs</a></li><li><a href="#traits">Traits</a></li><li><a href="#functions">Functions</a></li></ul></div><div id="sidebar-vars" data-name="rand" data-ty="mod" data-relpath=""></div><script defer src="sidebar-items.js"></script></div></nav><main><div class="width-limiter"><div class="sub-container"><a class="sub-logo-container" href="../rand/index.html"><img src="https://www.rust-lang.org/logos/rust-logo-128x128-blk.png" alt="logo"></a><nav class="sub"><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!" aria-haspopup="menu" title="themes"><img width="18" height="18" alt="Pick another theme!" src="../brush.svg"></button><div id="theme-choices" role="menu"></div></div><form class="search-form"><div class="search-container"><div> |
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| <details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Utilities for random number generation</p> |
| <p>Rand provides utilities to generate random numbers, to convert them to |
| useful types and distributions, and some randomness-related algorithms.</p> |
| <h2 id="quick-start" class="section-header"><a href="#quick-start">Quick Start</a></h2> |
| <p>To get you started quickly, the easiest and highest-level way to get |
| a random value is to use <a href="fn.random.html" title="random()"><code>random()</code></a>; alternatively you can use |
| <a href="fn.thread_rng.html" title="thread_rng()"><code>thread_rng()</code></a>. The <a href="trait.Rng.html" title="Rng"><code>Rng</code></a> trait provides a useful API on all RNGs, while |
| the <a href="distributions/index.html" title="distributions"><code>distributions</code></a> and <a href="seq/index.html" title="seq"><code>seq</code></a> modules provide further |
| functionality on top of RNGs.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use</span> <span class="ident">rand::prelude</span>::<span class="kw-2">*</span>; |
| |
| <span class="kw">if</span> <span class="ident">rand::random</span>() { <span class="comment">// generates a boolean</span> |
| <span class="comment">// Try printing a random unicode code point (probably a bad idea)!</span> |
| <span class="macro">println!</span>(<span class="string">"char: {}"</span>, <span class="ident">rand::random</span>::<span class="op"><</span><span class="ident">char</span><span class="op">></span>()); |
| } |
| |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident">rand::thread_rng</span>(); |
| <span class="kw">let</span> <span class="ident">y</span>: <span class="ident">f64</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">gen</span>(); <span class="comment">// generates a float between 0 and 1</span> |
| |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">nums</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">i32</span><span class="op">></span> <span class="op">=</span> (<span class="number">1</span>..<span class="number">100</span>).<span class="ident">collect</span>(); |
| <span class="ident">nums</span>.<span class="ident">shuffle</span>(<span class="kw-2">&mut</span> <span class="ident">rng</span>);</code></pre></div> |
| <h2 id="the-book" class="section-header"><a href="#the-book">The Book</a></h2> |
| <p>For the user guide and further documentation, please read |
| <a href="https://rust-random.github.io/book">The Rust Rand Book</a>.</p> |
| </div></details><h2 id="modules" class="small-section-header"><a href="#modules">Modules</a></h2> |
| <div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="mod" href="distributions/index.html" title="rand::distributions mod">distributions</a></div><div class="item-right docblock-short"><p>Generating random samples from probability distributions</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="mod" href="prelude/index.html" title="rand::prelude mod">prelude</a></div><div class="item-right docblock-short"><p>Convenience re-export of common members</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="mod" href="rngs/index.html" title="rand::rngs mod">rngs</a></div><div class="item-right docblock-short"><p>Random number generators and adapters</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="mod" href="seq/index.html" title="rand::seq mod">seq</a></div><div class="item-right docblock-short"><p>Sequence-related functionality</p> |
| </div></div></div><h2 id="structs" class="small-section-header"><a href="#structs">Structs</a></h2> |
| <div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.Error.html" title="rand::Error struct">Error</a></div><div class="item-right docblock-short"><p>Error type of random number generators</p> |
| </div></div></div><h2 id="traits" class="small-section-header"><a href="#traits">Traits</a></h2> |
| <div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.CryptoRng.html" title="rand::CryptoRng trait">CryptoRng</a></div><div class="item-right docblock-short"><p>A marker trait used to indicate that an <a href="trait.RngCore.html" title="RngCore"><code>RngCore</code></a> or <a href="../rand_core/block/trait.BlockRngCore.html"><code>BlockRngCore</code></a> |
| implementation is supposed to be cryptographically secure.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.Fill.html" title="rand::Fill trait">Fill</a></div><div class="item-right docblock-short"><p>Types which may be filled with random data</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.Rng.html" title="rand::Rng trait">Rng</a></div><div class="item-right docblock-short"><p>An automatically-implemented extension trait on <a href="trait.RngCore.html" title="RngCore"><code>RngCore</code></a> providing high-level |
| generic methods for sampling values and other convenience methods.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.RngCore.html" title="rand::RngCore trait">RngCore</a></div><div class="item-right docblock-short"><p>The core of a random number generator.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.SeedableRng.html" title="rand::SeedableRng trait">SeedableRng</a></div><div class="item-right docblock-short"><p>A random number generator that can be explicitly seeded.</p> |
| </div></div></div><h2 id="functions" class="small-section-header"><a href="#functions">Functions</a></h2> |
| <div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="fn" href="fn.random.html" title="rand::random fn">random</a><span class="stab portability" title="This is supported on crate features `std` and `std_rng` only"><code>std</code> and <code>std_rng</code></span></div><div class="item-right docblock-short"><p>Generates a random value using the thread-local random number generator.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="fn" href="fn.thread_rng.html" title="rand::thread_rng fn">thread_rng</a><span class="stab portability" title="This is supported on crate features `std` and `std_rng` only"><code>std</code> and <code>std_rng</code></span></div><div class="item-right docblock-short"><p>Retrieve the lazily-initialized thread-local random number generator, |
| seeded by the system. Intended to be used in method chaining style, |
| e.g. <code>thread_rng().gen::<i32>()</code>, or cached locally, e.g. |
| <code>let mut rng = thread_rng();</code>. Invoked by the <code>Default</code> trait, making |
| <code>ThreadRng::default()</code> equivalent.</p> |
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