pumpkin/rand/distributions/struct.WeightedChoice.html
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<h1 class='fqn'><span class='in-band'>Struct <a href='../index.html'>rand</a>::<wbr><a href='index.html'>distributions</a>::<wbr><a class='struct' href=''>WeightedChoice</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 id='src-558' class='srclink' href='../../src/rand/distributions/mod.rs.html#116-119' title='goto source code'>[src]</a></span></h1>
<pre class='rust struct'>pub struct WeightedChoice&lt;'a, T: 'a&gt; {
// some fields omitted
}</pre><div class='docblock'><p>A distribution that selects from a finite collection of weighted items.</p>
<p>Each item has an associated weight that influences how likely it
is to be chosen: higher weight is more likely.</p>
<p>The <code>Clone</code> restriction is a limitation of the <code>Sample</code> and
<code>IndependentSample</code> traits. Note that <code>&amp;T</code> is (cheaply) <code>Clone</code> for
all <code>T</code>, as is <code>u32</code>, so one can store references or indices into
another vector.</p>
<h1 id='example' class='section-header'><a href='#example'>Example</a></h1>
<pre class='rust rust-example-rendered'>
<span class='kw'>use</span> <span class='ident'>rand</span>::<span class='ident'>distributions</span>::{<span class='ident'>Weighted</span>, <span class='ident'>WeightedChoice</span>, <span class='ident'>IndependentSample</span>};
<span class='kw'>let</span> <span class='kw-2'>mut</span> <span class='ident'>items</span> <span class='op'>=</span> <span class='macro'>vec</span><span class='macro'>!</span>(<span class='ident'>Weighted</span> { <span class='ident'>weight</span>: <span class='number'>2</span>, <span class='ident'>item</span>: <span class='string'>&#39;a&#39;</span> },
<span class='ident'>Weighted</span> { <span class='ident'>weight</span>: <span class='number'>4</span>, <span class='ident'>item</span>: <span class='string'>&#39;b&#39;</span> },
<span class='ident'>Weighted</span> { <span class='ident'>weight</span>: <span class='number'>1</span>, <span class='ident'>item</span>: <span class='string'>&#39;c&#39;</span> });
<span class='kw'>let</span> <span class='ident'>wc</span> <span class='op'>=</span> <span class='ident'>WeightedChoice</span>::<span class='ident'>new</span>(<span class='kw-2'>&amp;</span><span class='kw-2'>mut</span> <span class='ident'>items</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='kw'>in</span> <span class='number'>0</span>..<span class='number'>16</span> {
<span class='comment'>// on average prints &#39;a&#39; 4 times, &#39;b&#39; 8 and &#39;c&#39; twice.</span>
<span class='macro'>println</span><span class='macro'>!</span>(<span class='string'>&quot;{}&quot;</span>, <span class='ident'>wc</span>.<span class='ident'>ind_sample</span>(<span class='kw-2'>&amp;</span><span class='kw-2'>mut</span> <span class='ident'>rng</span>));
}</pre>
</div><h2 id='methods'>Methods</h2><h3 class='impl'><code>impl&lt;'a, T: <a class='trait' href='https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html' title='core::clone::Clone'>Clone</a>&gt; <a class='struct' href='../../rand/distributions/struct.WeightedChoice.html' title='rand::distributions::WeightedChoice'>WeightedChoice</a>&lt;'a, T&gt;</code></h3><div class='impl-items'><h4 id='method.new' class='method'><code>fn <a href='#method.new' class='fnname'>new</a>(items: <a class='primitive' href='https://doc.rust-lang.org/nightly/std/primitive.slice.html'>&amp;'a mut [</a><a class='struct' href='../../rand/distributions/struct.Weighted.html' title='rand::distributions::Weighted'>Weighted</a>&lt;T&gt;<a class='primitive' href='https://doc.rust-lang.org/nightly/std/primitive.slice.html'>]</a>) -&gt; <a class='struct' href='../../rand/distributions/struct.WeightedChoice.html' title='rand::distributions::WeightedChoice'>WeightedChoice</a>&lt;'a, T&gt;</code></h4>
<div class='docblock'><p>Create a new <code>WeightedChoice</code>.</p>
<p>Panics if:
- <code>v</code> is empty
- the total weight is 0
- the total weight is larger than a <code>u32</code> can contain.</p>
</div></div><h2 id='implementations'>Trait Implementations</h2><h3 class='impl'><code>impl&lt;'a, T: <a class='trait' href='https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html' title='core::clone::Clone'>Clone</a>&gt; <a class='trait' href='../../rand/distributions/trait.Sample.html' title='rand::distributions::Sample'>Sample</a>&lt;T&gt; for <a class='struct' href='../../rand/distributions/struct.WeightedChoice.html' title='rand::distributions::WeightedChoice'>WeightedChoice</a>&lt;'a, T&gt;</code></h3><div class='impl-items'><h4 id='method.sample' class='method'><code>fn <a href='../../rand/distributions/trait.Sample.html#tymethod.sample' class='fnname'>sample</a>&lt;R: <a class='trait' href='../../rand/trait.Rng.html' title='rand::Rng'>Rng</a>&gt;(&amp;mut self, rng: &amp;mut R) -&gt; T</code></h4>
</div><h3 class='impl'><code>impl&lt;'a, T: <a class='trait' href='https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html' title='core::clone::Clone'>Clone</a>&gt; <a class='trait' href='../../rand/distributions/trait.IndependentSample.html' title='rand::distributions::IndependentSample'>IndependentSample</a>&lt;T&gt; for <a class='struct' href='../../rand/distributions/struct.WeightedChoice.html' title='rand::distributions::WeightedChoice'>WeightedChoice</a>&lt;'a, T&gt;</code></h3><div class='impl-items'><h4 id='method.ind_sample' class='method'><code>fn <a href='../../rand/distributions/trait.IndependentSample.html#tymethod.ind_sample' class='fnname'>ind_sample</a>&lt;R: <a class='trait' href='../../rand/trait.Rng.html' title='rand::Rng'>Rng</a>&gt;(&amp;self, rng: &amp;mut R) -&gt; T</code></h4>
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