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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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                       [<span class='inner'>&#x2212;</span>]
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               </span><a class='srclink' href='../src/rand/lib.rs.html#955-957' title='goto source code'>[src]</a></span></h1>
<pre class='rust fn'>pub fn random&lt;T:&nbsp;<a class="trait" href="../rand/trait.Rand.html" title="trait rand::Rand">Rand</a>&gt;() -&gt; T</pre><div class='docblock'><p>Generates a random value using the thread-local random number generator.</p>
<p><code>random()</code> can generate various types of random things, and so may require
type hinting to generate the specific type you want.</p>
<p>This function uses the thread local random number generator. This means
that if you're calling <code>random()</code> in a loop, caching the generator can
increase performance. An example is shown below.</p>
<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
<pre class="rust rust-example-rendered">
<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">&lt;</span><span class="ident">u8</span><span class="op">&gt;</span>();
<span class="macro">println</span><span class="macro">!</span>(<span class="string">&quot;{}&quot;</span>, <span class="ident">x</span>);

<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">&lt;</span><span class="ident">f64</span><span class="op">&gt;</span>();
<span class="macro">println</span><span class="macro">!</span>(<span class="string">&quot;{}&quot;</span>, <span class="ident">y</span>);

<span class="kw">if</span> <span class="ident">rand</span>::<span class="ident">random</span>() { <span class="comment">// generates a boolean</span>
    <span class="macro">println</span><span class="macro">!</span>(<span class="string">&quot;Better lucky than good!&quot;</span>);
}</pre>
<p>Caching the thread local random number generator:</p>

<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">rand</span>::<span class="ident">Rng</span>;

<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>];

<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>() {
    <span class="kw-2">*</span><span class="ident">x</span> <span class="op">=</span> <span class="ident">rand</span>::<span class="ident">random</span>()
}

<span class="comment">// can be made faster by caching thread_rng</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</span>::<span class="ident">thread_rng</span>();

<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>() {
    <span class="kw-2">*</span><span class="ident">x</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">gen</span>();
}</pre>
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