1 <!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="Generates a random value using the thread-local random number generator."><title>random in bdk_chain::bitcoin::secp256k1::rand::prelude - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../../../../../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../../../../../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../../../../../static.files/rustdoc-46132b98.css"><meta name="rustdoc-vars" data-root-path="../../../../../" data-static-root-path="../../../../../static.files/" data-current-crate="bdk_chain" data-themes="" data-resource-suffix="" data-rustdoc-version="1.86.0-nightly (824759493 2025-01-09)" data-channel="nightly" data-search-js="search-75f5ac3e.js" data-settings-js="settings-0f613d39.js" ><script src="../../../../../static.files/storage-59e33391.js"></script><script defer src="sidebar-items.js"></script><script defer src="../../../../../static.files/main-5f194d8c.js"></script><noscript><link rel="stylesheet" href="../../../../../static.files/noscript-893ab5e7.css"></noscript><link rel="alternate icon" type="image/png" href="../../../../../static.files/favicon-32x32-6580c154.png"><link rel="icon" type="image/svg+xml" href="../../../../../static.files/favicon-044be391.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" title="show sidebar"></button><a class="logo-container" href="../../../../../bdk_chain/index.html"><img src="https://github.com/bitcoindevkit/bdk/raw/master/static/bdk.png" alt=""></a></nav><nav class="sidebar"><div class="sidebar-crate"><a class="logo-container" href="../../../../../bdk_chain/index.html"><img src="https://github.com/bitcoindevkit/bdk/raw/master/static/bdk.png" alt="logo"></a><h2><a href="../../../../../bdk_chain/index.html">bdk_<wbr>chain</a><span class="version">0.21.1</span></h2></div><div class="sidebar-elems"><section id="rustdoc-toc"><h2 class="location"><a href="#">random</a></h2><h3><a href="#">Sections</a></h3><ul class="block top-toc"><li><a href="#provided-implementations" title="Provided implementations">Provided implementations</a></li><li><a href="#examples" title="Examples">Examples</a></li></ul></section><div id="rustdoc-modnav"><h2><a href="index.html">In bdk_<wbr>chain::<wbr>bitcoin::<wbr>secp256k1::<wbr>rand::<wbr>prelude</a></h2></div></div></nav><div class="sidebar-resizer"></div><main><div class="width-limiter"><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><span class="rustdoc-breadcrumbs"><a href="../../../../index.html">bdk_chain</a>::<wbr><a href="../../../index.html">bitcoin</a>::<wbr><a href="../../index.html">secp256k1</a>::<wbr><a href="../index.html">rand</a>::<wbr><a href="index.html">prelude</a></span><h1>Function <span class="fn">random</span><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"><a class="src" href="https://rust-random.github.io/rand/src/rand/lib.rs.html#183-184">Source</a> </span></div><pre class="rust item-decl"><code>pub fn random<T>() -> T<div class="where">where
2 <a class="struct" href="../distributions/struct.Standard.html" title="struct bdk_chain::bitcoin::secp256k1::rand::distributions::Standard">Standard</a>: <a class="trait" href="../distributions/trait.Distribution.html" title="trait bdk_chain::bitcoin::secp256k1::rand::distributions::Distribution">Distribution</a><T>,</div></code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Generates a random value using the thread-local random number generator.</p>
3 <p>This is simply a shortcut for <code>thread_rng().gen()</code>. See <a href="../fn.thread_rng.html" title="fn bdk_chain::bitcoin::secp256k1::rand::thread_rng"><code>thread_rng</code></a> for
4 documentation of the entropy source and <a href="../distributions/struct.Standard.html" title="struct bdk_chain::bitcoin::secp256k1::rand::distributions::Standard"><code>Standard</code></a> for documentation of
5 distributions and type-specific generation.</p>
6 <h2 id="provided-implementations"><a class="doc-anchor" href="#provided-implementations">§</a>Provided implementations</h2>
7 <p>The following types have provided implementations that
8 generate values with the following ranges and distributions:</p>
10 <li>Integers (<code>i32</code>, <code>u32</code>, <code>isize</code>, <code>usize</code>, etc.): Uniformly distributed
11 over all values of the type.</li>
12 <li><code>char</code>: Uniformly distributed over all Unicode scalar values, i.e. all
13 code points in the range <code>0...0x10_FFFF</code>, except for the range
14 <code>0xD800...0xDFFF</code> (the surrogate code points). This includes
15 unassigned/reserved code points.</li>
16 <li><code>bool</code>: Generates <code>false</code> or <code>true</code>, each with probability 0.5.</li>
17 <li>Floating point types (<code>f32</code> and <code>f64</code>): Uniformly distributed in the
18 half-open range <code>[0, 1)</code>. See notes below.</li>
19 <li>Wrapping integers (<code>Wrapping<T></code>), besides the type identical to their
20 normal integer variants.</li>
22 <p>Also supported is the generation of the following
23 compound types where all component types are supported:</p>
25 <li>Tuples (up to 12 elements): each element is generated sequentially.</li>
26 <li>Arrays (up to 32 elements): each element is generated sequentially;
27 see also <a href="../trait.Rng.html#method.fill" title="method bdk_chain::bitcoin::secp256k1::rand::Rng::fill"><code>Rng::fill</code></a> which supports arbitrary array length for integer
28 types and tends to be faster for <code>u32</code> and smaller types.</li>
29 <li><code>Option<T></code> first generates a <code>bool</code>, and if true generates and returns
30 <code>Some(value)</code> where <code>value: T</code>, otherwise returning <code>None</code>.</li>
32 <h2 id="examples"><a class="doc-anchor" href="#examples">§</a>Examples</h2>
33 <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">let </span>x = rand::random::<u8>();
34 <span class="macro">println!</span>(<span class="string">"{}"</span>, x);
36 <span class="kw">let </span>y = rand::random::<f64>();
37 <span class="macro">println!</span>(<span class="string">"{}"</span>, y);
39 <span class="kw">if </span>rand::random() { <span class="comment">// generates a boolean
40 </span><span class="macro">println!</span>(<span class="string">"Better lucky than good!"</span>);
42 <p>If you’re calling <code>random()</code> in a loop, caching the generator as in the
43 following example can increase performance.</p>
45 <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rand::Rng;
47 <span class="kw">let </span><span class="kw-2">mut </span>v = <span class="macro">vec!</span>[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>];
49 <span class="kw">for </span>x <span class="kw">in </span>v.iter_mut() {
50 <span class="kw-2">*</span>x = rand::random()
53 <span class="comment">// can be made faster by caching thread_rng
55 </span><span class="kw">let </span><span class="kw-2">mut </span>rng = rand::thread_rng();
57 <span class="kw">for </span>x <span class="kw">in </span>v.iter_mut() {
58 <span class="kw-2">*</span>x = rng.gen();
60 </div></details></section></div></main></body></html>
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