mentat/edn/intern_set/struct.InternSet.html
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<p class='location'>Struct InternSet</p><div class="sidebar-elems"><div class="block items"><a class="sidebar-title" href="#methods">Methods</a><div class="sidebar-links"><a href="#method.new">new</a><a href="#method.intern">intern</a></div><a class="sidebar-title" href="#deref-methods">Methods from Deref&lt;Target=HashSet&lt;ValueRc&lt;T&gt;&gt;&gt;</a><div class="sidebar-links"><a href="#method.hasher">hasher</a><a href="#method.capacity">capacity</a><a href="#method.iter">iter</a><a href="#method.difference">difference</a><a href="#method.symmetric_difference">symmetric_difference</a><a href="#method.intersection">intersection</a><a href="#method.union">union</a><a href="#method.len">len</a><a href="#method.is_empty">is_empty</a><a href="#method.contains">contains</a><a href="#method.get">get</a><a href="#method.is_disjoint">is_disjoint</a><a href="#method.is_subset">is_subset</a><a href="#method.is_superset">is_superset</a></div><a class="sidebar-title" href="#implementations">Trait Implementations</a><div class="sidebar-links"><a href="#impl-Clone">Clone</a><a href="#impl-Debug">Debug</a><a href="#impl-Default">Default</a><a href="#impl-Eq">Eq</a><a href="#impl-PartialEq">PartialEq</a><a href="#impl-Deref">Deref</a><a href="#impl-DerefMut">DerefMut</a></div></div><p class='location'><a href='../index.html'>edn</a>::<wbr><a href='index.html'>intern_set</a></p><script>window.sidebarCurrent = {name: 'InternSet', ty: 'struct', relpath: ''};</script><script defer src="sidebar-items.js"></script></div>
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<h1 class='fqn'><span class='in-band'>Struct <a href='../index.html'>edn</a>::<wbr><a href='index.html'>intern_set</a>::<wbr><a class="struct" href=''>InternSet</a></span><span class='out-of-band'><span id='render-detail'>
<a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">
[<span class='inner'>&#x2212;</span>]
</a>
</span><a class='srclink' href='../../src/edn/intern_set.rs.html#32-34' title='goto source code'>[src]</a></span></h1>
<pre class='rust struct'>pub struct InternSet&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span> { /* fields omitted */ }</pre><div class='docblock'><p>An <code>InternSet</code> allows to &quot;intern&quot; some potentially large values, maintaining a single value
instance owned by the <code>InternSet</code> and leaving consumers with lightweight ref-counted handles to
the large owned value. This can avoid expensive clone() operations.</p>
<p>In Mentat, such large values might be strings or arbitrary [a v] pairs.</p>
<p>See https://en.wikipedia.org/wiki/String_interning for discussion.</p>
</div>
<h2 id='methods' class='small-section-header'>
Methods<a href='#methods' class='anchor'></a>
</h2>
<h3 id='impl' class='impl'><span class='in-band'><code>impl&lt;T&gt; <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></code><a href='#impl' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#50-84' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.new' class="method"><span id='new.v' class='invisible'><code>pub fn <a href='#method.new' class='fnname'>new</a>() -&gt; <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#51-55' title='goto source code'>[src]</a></span></h4>
<h4 id='method.intern' class="method"><span id='intern.v' class='invisible'><code>pub fn <a href='#method.intern' class='fnname'>intern</a>&lt;R:&nbsp;<a class="trait" href="https://doc.rust-lang.org/nightly/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a>&lt;<a class="type" href="../../edn/value_rc/type.ValueRc.html" title="type edn::value_rc::ValueRc">ValueRc</a>&lt;T&gt;&gt;&gt;(&amp;mut self, value: R) -&gt; <a class="type" href="../../edn/value_rc/type.ValueRc.html" title="type edn::value_rc::ValueRc">ValueRc</a>&lt;T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#76-83' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Intern a value, providing a ref-counted handle to the interned value.</p>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">edn</span>::{<span class="ident">InternSet</span>, <span class="ident">ValueRc</span>};
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">s</span> <span class="op">=</span> <span class="ident">InternSet</span>::<span class="ident">new</span>();
<span class="kw">let</span> <span class="ident">one</span> <span class="op">=</span> <span class="string">&quot;foo&quot;</span>.<span class="ident">to_string</span>();
<span class="kw">let</span> <span class="ident">two</span> <span class="op">=</span> <span class="ident">ValueRc</span>::<span class="ident">new</span>(<span class="string">&quot;foo&quot;</span>.<span class="ident">to_string</span>());
<span class="kw">let</span> <span class="ident">out_one</span> <span class="op">=</span> <span class="ident">s</span>.<span class="ident">intern</span>(<span class="ident">one</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">out_one</span>, <span class="ident">two</span>);
<span class="comment">// assert!(!&amp;out_one.ptr_eq(&amp;two)); // Nightly-only.</span>
<span class="kw">let</span> <span class="ident">out_two</span> <span class="op">=</span> <span class="ident">s</span>.<span class="ident">intern</span>(<span class="ident">two</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">out_one</span>, <span class="ident">out_two</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="number">1</span>, <span class="ident">s</span>.<span class="ident">len</span>());
<span class="comment">// assert!(&amp;out_one.ptr_eq(&amp;out_two)); // Nightly-only.</span></pre>
</div></div>
<h2 id='deref-methods' class='small-section-header'>
Methods from <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/deref/trait.Deref.html" title="trait core::ops::deref::Deref">Deref</a>&lt;Target = <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.HashSet.html" title="struct std::collections::hash::set::HashSet">HashSet</a>&lt;<a class="type" href="../../edn/value_rc/type.ValueRc.html" title="type edn::value_rc::ValueRc">ValueRc</a>&lt;T&gt;&gt;&gt;<a href='#deref-methods' class='anchor'></a>
</h2>
<div class='impl-items'></div><div class='impl-items'><h4 id='method.hasher' class="method"><div class="important-traits"><div class='tooltip'><span class='tooltiptext'>Important traits for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;'a mut </a>R</span></div><div class="content hidden"><h3 class="important">Important traits for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;'a mut </a>R</h3><code class="content"><span class="where fmt-newline">impl&lt;'a, R&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/std/io/trait.Read.html" title="trait std::io::Read">Read</a> for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;'a mut </a>R <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;R: <a class="trait" href="https://doc.rust-lang.org/nightly/std/io/trait.Read.html" title="trait std::io::Read">Read</a> + ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,&nbsp;</span></span><span class="where fmt-newline">impl&lt;'a, W&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/std/io/trait.Write.html" title="trait std::io::Write">Write</a> for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;'a mut </a>W <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;W: <a class="trait" href="https://doc.rust-lang.org/nightly/std/io/trait.Write.html" title="trait std::io::Write">Write</a> + ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,&nbsp;</span></span><span class="where fmt-newline">impl&lt;'a, I&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html" title="trait core::iter::iterator::Iterator">Iterator</a> for <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;'a mut </a>I <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;I: <a class="trait" href="https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html" title="trait core::iter::iterator::Iterator">Iterator</a> + ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,&nbsp;</span></span><span class="where fmt-newline"> type <a href='https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = &lt;I as <a class="trait" href="https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html" title="trait core::iter::iterator::Iterator">Iterator</a>&gt;::<a class="type" href="https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html#associatedtype.Item" title="type core::iter::iterator::Iterator::Item">Item</a>;</span></code></div></div><span id='hasher.v' class='invisible'><code>pub fn <a href='#method.hasher' class='fnname'>hasher</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;</a>S</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.9.0'>1.9.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#234-236' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns a reference to the set's <a href="../../std/hash/trait.BuildHasher.html"><code>BuildHasher</code></a>.</p>
<h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">hash_map</span>::<span class="ident">RandomState</span>;
<span class="kw">let</span> <span class="ident">hasher</span> <span class="op">=</span> <span class="ident">RandomState</span>::<span class="ident">new</span>();
<span class="kw">let</span> <span class="ident">set</span>: <span class="ident">HashSet</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">with_hasher</span>(<span class="ident">hasher</span>);
<span class="kw">let</span> <span class="ident">hasher</span>: <span class="kw-2">&amp;</span><span class="ident">RandomState</span> <span class="op">=</span> <span class="ident">set</span>.<span class="ident">hasher</span>();</pre>
</div><h4 id='method.capacity' class="method"><span id='capacity.v' class='invisible'><code>pub fn <a href='#method.capacity' class='fnname'>capacity</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#249-251' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns the number of elements the set can hold without reallocating.</p>
<h1 id="examples-1" class="section-header"><a href="#examples-1">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">set</span>: <span class="ident">HashSet</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">with_capacity</span>(<span class="number">100</span>);
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">capacity</span>() <span class="op">&gt;=</span> <span class="number">100</span>);</pre>
</div><h4 id='method.reserve' class="method"><span id='reserve.v' class='invisible'><code>pub fn <a href='#method.reserve' class='fnname'>reserve</a>(&amp;mut self, additional: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a>)</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#270-272' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Reserves capacity for at least <code>additional</code> more elements to be inserted
in the <code>HashSet</code>. The collection may reserve more space to avoid
frequent reallocations.</p>
<h1 id="panics" class="section-header"><a href="#panics">Panics</a></h1>
<p>Panics if the new allocation size overflows <code>usize</code>.</p>
<h1 id="examples-2" class="section-header"><a href="#examples-2">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span>: <span class="ident">HashSet</span><span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="ident">set</span>.<span class="ident">reserve</span>(<span class="number">10</span>);
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">capacity</span>() <span class="op">&gt;=</span> <span class="number">10</span>);</pre>
</div><h4 id='method.shrink_to_fit' class="method"><span id='shrink_to_fit.v' class='invisible'><code>pub fn <a href='#method.shrink_to_fit' class='fnname'>shrink_to_fit</a>(&amp;mut self)</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#291-293' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Shrinks the capacity of the set as much as possible. It will drop
down as much as possible while maintaining the internal rules
and possibly leaving some space in accordance with the resize policy.</p>
<h1 id="examples-3" class="section-header"><a href="#examples-3">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">with_capacity</span>(<span class="number">100</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">1</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">2</span>);
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">capacity</span>() <span class="op">&gt;=</span> <span class="number">100</span>);
<span class="ident">set</span>.<span class="ident">shrink_to_fit</span>();
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">capacity</span>() <span class="op">&gt;=</span> <span class="number">2</span>);</pre>
</div><h4 id='method.iter' class="method"><div class="important-traits"><div class='tooltip'><span class='tooltiptext'>Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Iter.html" title="struct std::collections::hash::set::Iter">Iter</a>&lt;'a, K&gt;</span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Iter.html" title="struct std::collections::hash::set::Iter">Iter</a>&lt;'a, K&gt;</h3><code class="content"><span class="where fmt-newline">impl&lt;'a, K&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html" title="trait core::iter::iterator::Iterator">Iterator</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Iter.html" title="struct std::collections::hash::set::Iter">Iter</a>&lt;'a, K&gt;</span><span class="where fmt-newline"> type <a href='https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;'a </a>K;</span></code></div></div><span id='iter.v' class='invisible'><code>pub fn <a href='#method.iter' class='fnname'>iter</a>(&amp;self) -&gt; <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Iter.html" title="struct std::collections::hash::set::Iter">Iter</a>&lt;T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#312-314' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>An iterator visiting all elements in arbitrary order.
The iterator element type is <code>&amp;'a T</code>.</p>
<h1 id="examples-4" class="section-header"><a href="#examples-4">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="string">&quot;a&quot;</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="string">&quot;b&quot;</span>);
<span class="comment">// Will print in an arbitrary order.</span>
<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="ident">set</span>.<span class="ident">iter</span>() {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">&quot;{}&quot;</span>, <span class="ident">x</span>);
}</pre>
</div><h4 id='method.difference' class="method"><div class="important-traits"><div class='tooltip'><span class='tooltiptext'>Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Difference.html" title="struct std::collections::hash::set::Difference">Difference</a>&lt;'a, T, S&gt;</span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Difference.html" title="struct std::collections::hash::set::Difference">Difference</a>&lt;'a, T, S&gt;</h3><code class="content"><span class="where fmt-newline">impl&lt;'a, T, S&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html" title="trait core::iter::iterator::Iterator">Iterator</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Difference.html" title="struct std::collections::hash::set::Difference">Difference</a>&lt;'a, T, S&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;S: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.BuildHasher.html" title="trait core::hash::BuildHasher">BuildHasher</a>,<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></span><span class="where fmt-newline"> type <a href='https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;'a </a>T;</span></code></div></div><span id='difference.v' class='invisible'><code>pub fn <a href='#method.difference' class='fnname'>difference</a>(&amp;'a self, other: &amp;'a <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.HashSet.html" title="struct std::collections::hash::set::HashSet">HashSet</a>&lt;T, S&gt;) -&gt; <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Difference.html" title="struct std::collections::hash::set::Difference">Difference</a>&lt;'a, T, S&gt;</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#340-345' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Visits the values representing the difference,
i.e. the values that are in <code>self</code> but not in <code>other</code>.</p>
<h1 id="examples-5" class="section-header"><a href="#examples-5">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">a</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">b</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">4</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="comment">// Can be seen as `a - b`.</span>
<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="ident">a</span>.<span class="ident">difference</span>(<span class="kw-2">&amp;</span><span class="ident">b</span>) {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">&quot;{}&quot;</span>, <span class="ident">x</span>); <span class="comment">// Print 1</span>
}
<span class="kw">let</span> <span class="ident">diff</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> <span class="ident">a</span>.<span class="ident">difference</span>(<span class="kw-2">&amp;</span><span class="ident">b</span>).<span class="ident">collect</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">diff</span>, [<span class="number">1</span>].<span class="ident">iter</span>().<span class="ident">collect</span>());
<span class="comment">// Note that difference is not symmetric,</span>
<span class="comment">// and `b - a` means something else:</span>
<span class="kw">let</span> <span class="ident">diff</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">difference</span>(<span class="kw-2">&amp;</span><span class="ident">a</span>).<span class="ident">collect</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">diff</span>, [<span class="number">4</span>].<span class="ident">iter</span>().<span class="ident">collect</span>());</pre>
</div><h4 id='method.symmetric_difference' class="method"><div class="important-traits"><div class='tooltip'><span class='tooltiptext'>Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.SymmetricDifference.html" title="struct std::collections::hash::set::SymmetricDifference">SymmetricDifference</a>&lt;'a, T, S&gt;</span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.SymmetricDifference.html" title="struct std::collections::hash::set::SymmetricDifference">SymmetricDifference</a>&lt;'a, T, S&gt;</h3><code class="content"><span class="where fmt-newline">impl&lt;'a, T, S&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html" title="trait core::iter::iterator::Iterator">Iterator</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.SymmetricDifference.html" title="struct std::collections::hash::set::SymmetricDifference">SymmetricDifference</a>&lt;'a, T, S&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;S: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.BuildHasher.html" title="trait core::hash::BuildHasher">BuildHasher</a>,<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></span><span class="where fmt-newline"> type <a href='https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;'a </a>T;</span></code></div></div><span id='symmetric_difference.v' class='invisible'><code>pub fn <a href='#method.symmetric_difference' class='fnname'>symmetric_difference</a>(<br>&nbsp;&nbsp;&nbsp;&nbsp;&amp;'a self, <br>&nbsp;&nbsp;&nbsp;&nbsp;other: &amp;'a <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.HashSet.html" title="struct std::collections::hash::set::HashSet">HashSet</a>&lt;T, S&gt;<br>) -&gt; <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.SymmetricDifference.html" title="struct std::collections::hash::set::SymmetricDifference">SymmetricDifference</a>&lt;'a, T, S&gt;</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#369-373' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Visits the values representing the symmetric difference,
i.e. the values that are in <code>self</code> or in <code>other</code> but not in both.</p>
<h1 id="examples-6" class="section-header"><a href="#examples-6">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">a</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">b</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">4</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="comment">// Print 1, 4 in arbitrary order.</span>
<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="ident">a</span>.<span class="ident">symmetric_difference</span>(<span class="kw-2">&amp;</span><span class="ident">b</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">diff1</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> <span class="ident">a</span>.<span class="ident">symmetric_difference</span>(<span class="kw-2">&amp;</span><span class="ident">b</span>).<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">diff2</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">symmetric_difference</span>(<span class="kw-2">&amp;</span><span class="ident">a</span>).<span class="ident">collect</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">diff1</span>, <span class="ident">diff2</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">diff1</span>, [<span class="number">1</span>, <span class="number">4</span>].<span class="ident">iter</span>().<span class="ident">collect</span>());</pre>
</div><h4 id='method.intersection' class="method"><div class="important-traits"><div class='tooltip'><span class='tooltiptext'>Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Intersection.html" title="struct std::collections::hash::set::Intersection">Intersection</a>&lt;'a, T, S&gt;</span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Intersection.html" title="struct std::collections::hash::set::Intersection">Intersection</a>&lt;'a, T, S&gt;</h3><code class="content"><span class="where fmt-newline">impl&lt;'a, T, S&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html" title="trait core::iter::iterator::Iterator">Iterator</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Intersection.html" title="struct std::collections::hash::set::Intersection">Intersection</a>&lt;'a, T, S&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;S: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.BuildHasher.html" title="trait core::hash::BuildHasher">BuildHasher</a>,<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></span><span class="where fmt-newline"> type <a href='https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;'a </a>T;</span></code></div></div><span id='intersection.v' class='invisible'><code>pub fn <a href='#method.intersection' class='fnname'>intersection</a>(<br>&nbsp;&nbsp;&nbsp;&nbsp;&amp;'a self, <br>&nbsp;&nbsp;&nbsp;&nbsp;other: &amp;'a <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.HashSet.html" title="struct std::collections::hash::set::HashSet">HashSet</a>&lt;T, S&gt;<br>) -&gt; <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Intersection.html" title="struct std::collections::hash::set::Intersection">Intersection</a>&lt;'a, T, S&gt;</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#394-399' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Visits the values representing the intersection,
i.e. the values that are both in <code>self</code> and <code>other</code>.</p>
<h1 id="examples-7" class="section-header"><a href="#examples-7">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">a</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">b</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">4</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="comment">// Print 2, 3 in arbitrary order.</span>
<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="ident">a</span>.<span class="ident">intersection</span>(<span class="kw-2">&amp;</span><span class="ident">b</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">intersection</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> <span class="ident">a</span>.<span class="ident">intersection</span>(<span class="kw-2">&amp;</span><span class="ident">b</span>).<span class="ident">collect</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">intersection</span>, [<span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">collect</span>());</pre>
</div><h4 id='method.union' class="method"><div class="important-traits"><div class='tooltip'><span class='tooltiptext'>Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Union.html" title="struct std::collections::hash::set::Union">Union</a>&lt;'a, T, S&gt;</span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Union.html" title="struct std::collections::hash::set::Union">Union</a>&lt;'a, T, S&gt;</h3><code class="content"><span class="where fmt-newline">impl&lt;'a, T, S&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html" title="trait core::iter::iterator::Iterator">Iterator</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Union.html" title="struct std::collections::hash::set::Union">Union</a>&lt;'a, T, S&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;S: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.BuildHasher.html" title="trait core::hash::BuildHasher">BuildHasher</a>,<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></span><span class="where fmt-newline"> type <a href='https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;'a </a>T;</span></code></div></div><span id='union.v' class='invisible'><code>pub fn <a href='#method.union' class='fnname'>union</a>(&amp;'a self, other: &amp;'a <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.HashSet.html" title="struct std::collections::hash::set::HashSet">HashSet</a>&lt;T, S&gt;) -&gt; <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Union.html" title="struct std::collections::hash::set::Union">Union</a>&lt;'a, T, S&gt;</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#420-422' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Visits the values representing the union,
i.e. all the values in <code>self</code> or <code>other</code>, without duplicates.</p>
<h1 id="examples-8" class="section-header"><a href="#examples-8">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">a</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">b</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">4</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="comment">// Print 1, 2, 3, 4 in arbitrary order.</span>
<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="ident">a</span>.<span class="ident">union</span>(<span class="kw-2">&amp;</span><span class="ident">b</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">union</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> <span class="ident">a</span>.<span class="ident">union</span>(<span class="kw-2">&amp;</span><span class="ident">b</span>).<span class="ident">collect</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">union</span>, [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>].<span class="ident">iter</span>().<span class="ident">collect</span>());</pre>
</div><h4 id='method.len' class="method"><span id='len.v' class='invisible'><code>pub fn <a href='#method.len' class='fnname'>len</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.usize.html">usize</a></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#437-439' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns the number of elements in the set.</p>
<h1 id="examples-9" class="section-header"><a href="#examples-9">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">v</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">v</span>.<span class="ident">len</span>(), <span class="number">0</span>);
<span class="ident">v</span>.<span class="ident">insert</span>(<span class="number">1</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">v</span>.<span class="ident">len</span>(), <span class="number">1</span>);</pre>
</div><h4 id='method.is_empty' class="method"><span id='is_empty.v' class='invisible'><code>pub fn <a href='#method.is_empty' class='fnname'>is_empty</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#454-456' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns true if the set contains no elements.</p>
<h1 id="examples-10" class="section-header"><a href="#examples-10">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">v</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">v</span>.<span class="ident">is_empty</span>());
<span class="ident">v</span>.<span class="ident">insert</span>(<span class="number">1</span>);
<span class="macro">assert</span><span class="macro">!</span>(<span class="op">!</span><span class="ident">v</span>.<span class="ident">is_empty</span>());</pre>
</div><h4 id='method.drain' class="method"><div class="important-traits"><div class='tooltip'><span class='tooltiptext'>Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Drain.html" title="struct std::collections::hash::set::Drain">Drain</a>&lt;'a, K&gt;</span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Drain.html" title="struct std::collections::hash::set::Drain">Drain</a>&lt;'a, K&gt;</h3><code class="content"><span class="where fmt-newline">impl&lt;'a, K&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html" title="trait core::iter::iterator::Iterator">Iterator</a> for <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Drain.html" title="struct std::collections::hash::set::Drain">Drain</a>&lt;'a, K&gt;</span><span class="where fmt-newline"> type <a href='https://doc.rust-lang.org/nightly/core/iter/iterator/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = K;</span></code></div></div><span id='drain.v' class='invisible'><code>pub fn <a href='#method.drain' class='fnname'>drain</a>(&amp;mut self) -&gt; <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.Drain.html" title="struct std::collections::hash::set::Drain">Drain</a>&lt;T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.6.0'>1.6.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#477-479' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Clears the set, returning all elements in an iterator.</p>
<h1 id="examples-11" class="section-header"><a href="#examples-11">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="macro">assert</span><span class="macro">!</span>(<span class="op">!</span><span class="ident">set</span>.<span class="ident">is_empty</span>());
<span class="comment">// print 1, 2, 3 in an arbitrary order</span>
<span class="kw">for</span> <span class="ident">i</span> <span class="kw">in</span> <span class="ident">set</span>.<span class="ident">drain</span>() {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">&quot;{}&quot;</span>, <span class="ident">i</span>);
}
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">is_empty</span>());</pre>
</div><h4 id='method.clear' class="method"><span id='clear.v' class='invisible'><code>pub fn <a href='#method.clear' class='fnname'>clear</a>(&amp;mut self)</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#494-496' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Clears the set, removing all values.</p>
<h1 id="examples-12" class="section-header"><a href="#examples-12">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">v</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="ident">v</span>.<span class="ident">insert</span>(<span class="number">1</span>);
<span class="ident">v</span>.<span class="ident">clear</span>();
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">v</span>.<span class="ident">is_empty</span>());</pre>
</div><h4 id='method.contains' class="method"><span id='contains.v' class='invisible'><code>pub fn <a href='#method.contains' class='fnname'>contains</a>&lt;Q&gt;(&amp;self, value: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;</a>Q) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a> <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;Q: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html" title="trait core::borrow::Borrow">Borrow</a>&lt;Q&gt;,&nbsp;</span></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#517-522' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns <code>true</code> if the set contains a value.</p>
<p>The value may be any borrowed form of the set's value type, but
<a href="../../std/hash/trait.Hash.html"><code>Hash</code></a> and <a href="../../std/cmp/trait.Eq.html"><code>Eq</code></a> on the borrowed form <em>must</em> match those for
the value type.</p>
<h1 id="examples-13" class="section-header"><a href="#examples-13">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">set</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">contains</span>(<span class="kw-2">&amp;</span><span class="number">1</span>), <span class="bool-val">true</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">contains</span>(<span class="kw-2">&amp;</span><span class="number">4</span>), <span class="bool-val">false</span>);</pre>
</div><h4 id='method.get' class="method"><span id='get.v' class='invisible'><code>pub fn <a href='#method.get' class='fnname'>get</a>&lt;Q&gt;(&amp;self, value: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;</a>Q) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;</a>T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;Q: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html" title="trait core::borrow::Borrow">Borrow</a>&lt;Q&gt;,&nbsp;</span></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.9.0'>1.9.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#543-548' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns a reference to the value in the set, if any, that is equal to the given value.</p>
<p>The value may be any borrowed form of the set's value type, but
<a href="../../std/hash/trait.Hash.html"><code>Hash</code></a> and <a href="../../std/cmp/trait.Eq.html"><code>Eq</code></a> on the borrowed form <em>must</em> match those for
the value type.</p>
<h1 id="examples-14" class="section-header"><a href="#examples-14">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">set</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">get</span>(<span class="kw-2">&amp;</span><span class="number">2</span>), <span class="prelude-val">Some</span>(<span class="kw-2">&amp;</span><span class="number">2</span>));
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">get</span>(<span class="kw-2">&amp;</span><span class="number">4</span>), <span class="prelude-val">None</span>);</pre>
</div><h4 id='method.is_disjoint' class="method"><span id='is_disjoint.v' class='invisible'><code>pub fn <a href='#method.is_disjoint' class='fnname'>is_disjoint</a>(&amp;self, other: &amp;<a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.HashSet.html" title="struct std::collections::hash::set::HashSet">HashSet</a>&lt;T, S&gt;) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#568-570' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns <code>true</code> if <code>self</code> has no elements in common with <code>other</code>.
This is equivalent to checking for an empty intersection.</p>
<h1 id="examples-15" class="section-header"><a href="#examples-15">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">a</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">b</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">a</span>.<span class="ident">is_disjoint</span>(<span class="kw-2">&amp;</span><span class="ident">b</span>), <span class="bool-val">true</span>);
<span class="ident">b</span>.<span class="ident">insert</span>(<span class="number">4</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">a</span>.<span class="ident">is_disjoint</span>(<span class="kw-2">&amp;</span><span class="ident">b</span>), <span class="bool-val">true</span>);
<span class="ident">b</span>.<span class="ident">insert</span>(<span class="number">1</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">a</span>.<span class="ident">is_disjoint</span>(<span class="kw-2">&amp;</span><span class="ident">b</span>), <span class="bool-val">false</span>);</pre>
</div><h4 id='method.is_subset' class="method"><span id='is_subset.v' class='invisible'><code>pub fn <a href='#method.is_subset' class='fnname'>is_subset</a>(&amp;self, other: &amp;<a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.HashSet.html" title="struct std::collections::hash::set::HashSet">HashSet</a>&lt;T, S&gt;) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#590-592' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns <code>true</code> if the set is a subset of another,
i.e. <code>other</code> contains at least all the values in <code>self</code>.</p>
<h1 id="examples-16" class="section-header"><a href="#examples-16">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">sup</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">is_subset</span>(<span class="kw-2">&amp;</span><span class="ident">sup</span>), <span class="bool-val">true</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">2</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">is_subset</span>(<span class="kw-2">&amp;</span><span class="ident">sup</span>), <span class="bool-val">true</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">4</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">is_subset</span>(<span class="kw-2">&amp;</span><span class="ident">sup</span>), <span class="bool-val">false</span>);</pre>
</div><h4 id='method.is_superset' class="method"><span id='is_superset.v' class='invisible'><code>pub fn <a href='#method.is_superset' class='fnname'>is_superset</a>(&amp;self, other: &amp;<a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.HashSet.html" title="struct std::collections::hash::set::HashSet">HashSet</a>&lt;T, S&gt;) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#616-618' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns <code>true</code> if the set is a superset of another,
i.e. <code>self</code> contains at least all the values in <code>other</code>.</p>
<h1 id="examples-17" class="section-header"><a href="#examples-17">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">sub</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">is_superset</span>(<span class="kw-2">&amp;</span><span class="ident">sub</span>), <span class="bool-val">false</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">0</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">1</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">is_superset</span>(<span class="kw-2">&amp;</span><span class="ident">sub</span>), <span class="bool-val">false</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">2</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">is_superset</span>(<span class="kw-2">&amp;</span><span class="ident">sub</span>), <span class="bool-val">true</span>);</pre>
</div><h4 id='method.insert' class="method"><span id='insert.v' class='invisible'><code>pub fn <a href='#method.insert' class='fnname'>insert</a>(&amp;mut self, value: T) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#638-640' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Adds a value to the set.</p>
<p>If the set did not have this value present, <code>true</code> is returned.</p>
<p>If the set did have this value present, <code>false</code> is returned.</p>
<h1 id="examples-18" class="section-header"><a href="#examples-18">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">2</span>), <span class="bool-val">true</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">2</span>), <span class="bool-val">false</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">len</span>(), <span class="number">1</span>);</pre>
</div><h4 id='method.replace' class="method"><span id='replace.v' class='invisible'><code>pub fn <a href='#method.replace' class='fnname'>replace</a>(&amp;mut self, value: T) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.9.0'>1.9.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#658-660' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Adds a value to the set, replacing the existing value, if any, that is equal to the given
one. Returns the replaced value.</p>
<h1 id="examples-19" class="section-header"><a href="#examples-19">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="ident">Vec</span>::<span class="op">&lt;</span><span class="ident">i32</span><span class="op">&gt;</span>::<span class="ident">new</span>());
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">get</span>(<span class="kw-2">&amp;</span>[][..]).<span class="ident">unwrap</span>().<span class="ident">capacity</span>(), <span class="number">0</span>);
<span class="ident">set</span>.<span class="ident">replace</span>(<span class="ident">Vec</span>::<span class="ident">with_capacity</span>(<span class="number">10</span>));
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">get</span>(<span class="kw-2">&amp;</span>[][..]).<span class="ident">unwrap</span>().<span class="ident">capacity</span>(), <span class="number">10</span>);</pre>
</div><h4 id='method.remove' class="method"><span id='remove.v' class='invisible'><code>pub fn <a href='#method.remove' class='fnname'>remove</a>&lt;Q&gt;(&amp;mut self, value: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;</a>Q) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a> <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;Q: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html" title="trait core::borrow::Borrow">Borrow</a>&lt;Q&gt;,&nbsp;</span></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#684-689' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Removes a value from the set. Returns <code>true</code> if the value was
present in the set.</p>
<p>The value may be any borrowed form of the set's value type, but
<a href="../../std/hash/trait.Hash.html"><code>Hash</code></a> and <a href="../../std/cmp/trait.Eq.html"><code>Eq</code></a> on the borrowed form <em>must</em> match those for
the value type.</p>
<h1 id="examples-20" class="section-header"><a href="#examples-20">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">2</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">remove</span>(<span class="kw-2">&amp;</span><span class="number">2</span>), <span class="bool-val">true</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">remove</span>(<span class="kw-2">&amp;</span><span class="number">2</span>), <span class="bool-val">false</span>);</pre>
</div><h4 id='method.take' class="method"><span id='take.v' class='invisible'><code>pub fn <a href='#method.take' class='fnname'>take</a>&lt;Q&gt;(&amp;mut self, value: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;</a>Q) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;Q: <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + ?<a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html" title="trait core::borrow::Borrow">Borrow</a>&lt;Q&gt;,&nbsp;</span></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.9.0'>1.9.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#710-715' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Removes and returns the value in the set, if any, that is equal to the given one.</p>
<p>The value may be any borrowed form of the set's value type, but
<a href="../../std/hash/trait.Hash.html"><code>Hash</code></a> and <a href="../../std/cmp/trait.Eq.html"><code>Eq</code></a> on the borrowed form <em>must</em> match those for
the value type.</p>
<h1 id="examples-21" class="section-header"><a href="#examples-21">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span>: <span class="ident">HashSet</span><span class="op">&lt;</span>_<span class="op">&gt;</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">take</span>(<span class="kw-2">&amp;</span><span class="number">2</span>), <span class="prelude-val">Some</span>(<span class="number">2</span>));
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">take</span>(<span class="kw-2">&amp;</span><span class="number">2</span>), <span class="prelude-val">None</span>);</pre>
</div><h4 id='method.retain' class="method"><span id='retain.v' class='invisible'><code>pub fn <a href='#method.retain' class='fnname'>retain</a>&lt;F&gt;(&amp;mut self, f: F) <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;F: <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/function/trait.FnMut.html" title="trait core::ops::function::FnMut">FnMut</a>(<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;</a>T) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a>,&nbsp;</span></code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.18.0'>1.18.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/std/collections/hash/set.rs.html#732-736' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Retains only the elements specified by the predicate.</p>
<p>In other words, remove all elements <code>e</code> such that <code>f(&amp;e)</code> returns <code>false</code>.</p>
<h1 id="examples-22" class="section-header"><a href="#examples-22">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="kw">use</span> <span class="ident">std</span>::<span class="ident">collections</span>::<span class="ident">HashSet</span>;
<span class="kw">let</span> <span class="ident">xs</span> <span class="op">=</span> [<span class="number">1</span>,<span class="number">2</span>,<span class="number">3</span>,<span class="number">4</span>,<span class="number">5</span>,<span class="number">6</span>];
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">set</span>: <span class="ident">HashSet</span><span class="op">&lt;</span><span class="ident">isize</span><span class="op">&gt;</span> <span class="op">=</span> <span class="ident">xs</span>.<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="ident">set</span>.<span class="ident">retain</span>(<span class="op">|</span><span class="kw-2">&amp;</span><span class="ident">k</span><span class="op">|</span> <span class="ident">k</span> <span class="op">%</span> <span class="number">2</span> <span class="op">==</span> <span class="number">0</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">len</span>(), <span class="number">3</span>);</pre>
</div></div>
<h2 id='implementations' class='small-section-header'>
Trait Implementations<a href='#implementations' class='anchor'></a>
</h2>
<h3 id='impl-Clone' class='impl'><span class='in-band'><code>impl&lt;T:&nbsp;<a class="trait" href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a> for <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></code><a href='#impl-Clone' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#31' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.clone' class="method"><span id='clone.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone' class='fnname'>clone</a>(&amp;self) -&gt; <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#31' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns a copy of the value. <a href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone">Read more</a></p>
</div><h4 id='method.clone_from' class="method"><span id='clone_from.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from' class='fnname'>clone_from</a>(&amp;mut self, source: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&amp;</a>Self)</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/core/clone.rs.html#112-114' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Performs copy-assignment from <code>source</code>. <a href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from">Read more</a></p>
</div></div><h3 id='impl-Debug' class='impl'><span class='in-band'><code>impl&lt;T:&nbsp;<a class="trait" href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a>&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a> for <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></code><a href='#impl-Debug' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#31' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.fmt' class="method"><span id='fmt.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt' class='fnname'>fmt</a>(&amp;self, __arg_0: &amp;mut <a class="struct" href="https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a>) -&gt; <a class="type" href="https://doc.rust-lang.org/nightly/core/fmt/type.Result.html" title="type core::fmt::Result">Result</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#31' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Formats the value using the given formatter. <a href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt">Read more</a></p>
</div></div><h3 id='impl-Default' class='impl'><span class='in-band'><code>impl&lt;T:&nbsp;<a class="trait" href="https://doc.rust-lang.org/nightly/core/default/trait.Default.html" title="trait core::default::Default">Default</a>&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/default/trait.Default.html" title="trait core::default::Default">Default</a> for <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></code><a href='#impl-Default' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#31' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.default' class="method"><span id='default.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/default/trait.Default.html#tymethod.default' class='fnname'>default</a>() -&gt; <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt;</code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#31' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Returns the &quot;default value&quot; for a type. <a href="https://doc.rust-lang.org/nightly/core/default/trait.Default.html#tymethod.default">Read more</a></p>
</div></div><h3 id='impl-Eq' class='impl'><span class='in-band'><code>impl&lt;T:&nbsp;<a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a>&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> for <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></code><a href='#impl-Eq' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#31' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'></div><h3 id='impl-PartialEq' class='impl'><span class='in-band'><code>impl&lt;T:&nbsp;<a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html" title="trait core::cmp::PartialEq">PartialEq</a>&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html" title="trait core::cmp::PartialEq">PartialEq</a> for <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></code><a href='#impl-PartialEq' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#31' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.eq' class="method"><span id='eq.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#tymethod.eq' class='fnname'>eq</a>(&amp;self, __arg_0: &amp;<a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt;) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#31' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>This method tests for <code>self</code> and <code>other</code> values to be equal, and is used by <code>==</code>. <a href="https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#tymethod.eq">Read more</a></p>
</div><h4 id='method.ne' class="method"><span id='ne.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/cmp/trait.PartialEq.html#method.ne' class='fnname'>ne</a>(&amp;self, __arg_0: &amp;<a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt;) -&gt; <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.bool.html">bool</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#31' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>This method tests for <code>!=</code>.</p>
</div></div><h3 id='impl-Deref' class='impl'><span class='in-band'><code>impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/deref/trait.Deref.html" title="trait core::ops::deref::Deref">Deref</a> for <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></code><a href='#impl-Deref' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#36-42' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='associatedtype.Target' class="type"><span id='Target.t' class='invisible'><code>type <a href='https://doc.rust-lang.org/nightly/core/ops/deref/trait.Deref.html#associatedtype.Target' class="type">Target</a> = <a class="struct" href="https://doc.rust-lang.org/nightly/std/collections/hash/set/struct.HashSet.html" title="struct std::collections::hash::set::HashSet">HashSet</a>&lt;<a class="type" href="../../edn/value_rc/type.ValueRc.html" title="type edn::value_rc::ValueRc">ValueRc</a>&lt;T&gt;&gt;</code></span></h4>
<div class='docblock'><p>The resulting type after dereferencing.</p>
</div><h4 id='method.deref' class="method"><span id='deref.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/ops/deref/trait.Deref.html#tymethod.deref' class='fnname'>deref</a>(&amp;self) -&gt; &amp;Self::<a class="type" href="https://doc.rust-lang.org/nightly/core/ops/deref/trait.Deref.html#associatedtype.Target" title="type core::ops::deref::Deref::Target">Target</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#39-41' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Dereferences the value.</p>
</div></div><h3 id='impl-DerefMut' class='impl'><span class='in-band'><code>impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/deref/trait.DerefMut.html" title="trait core::ops::deref::DerefMut">DerefMut</a> for <a class="struct" href="../../edn/intern_set/struct.InternSet.html" title="struct edn::intern_set::InternSet">InternSet</a>&lt;T&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="https://doc.rust-lang.org/nightly/core/cmp/trait.Eq.html" title="trait core::cmp::Eq">Eq</a> + <a class="trait" href="https://doc.rust-lang.org/nightly/core/hash/trait.Hash.html" title="trait core::hash::Hash">Hash</a>,&nbsp;</span></code><a href='#impl-DerefMut' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#44-48' title='goto source code'>[src]</a></span></h3>
<div class='impl-items'><h4 id='method.deref_mut' class="method"><span id='deref_mut.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/ops/deref/trait.DerefMut.html#tymethod.deref_mut' class='fnname'>deref_mut</a>(&amp;mut self) -&gt; &amp;mut Self::<a class="type" href="https://doc.rust-lang.org/nightly/core/ops/deref/trait.Deref.html#associatedtype.Target" title="type core::ops::deref::Deref::Target">Target</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/edn/intern_set.rs.html#45-47' title='goto source code'>[src]</a></span></h4>
<div class='docblock'><p>Mutably dereferences the value.</p>
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