<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="API documentation for the Rust `HashSet` struct in crate `std`."><meta name="keywords" content="rust, rustlang, rust-lang, HashSet"><title>std::collections::hash_set::HashSet - Rust</title><link rel="stylesheet" type="text/css" href="../../../normalize.css"><link rel="stylesheet" type="text/css" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../../dark.css"><link rel="stylesheet" type="text/css" href="../../../light.css" id="themeStyle"><script src="../../../storage.js"></script><link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"></head><body class="rustdoc struct"><!--[if lte IE 8]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu">☰</div><a href='../../../std/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a><p class='location'>Struct HashSet</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.with_capacity">with_capacity</a><a href="#method.with_hasher">with_hasher</a><a href="#method.with_capacity_and_hasher">with_capacity_and_hasher</a><a href="#method.hasher">hasher</a><a href="#method.capacity">capacity</a><a href="#method.reserve">reserve</a><a href="#method.shrink_to_fit">shrink_to_fit</a><a href="#method.shrink_to">shrink_to</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.drain">drain</a><a href="#method.clear">clear</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><a href="#method.insert">insert</a><a href="#method.replace">replace</a><a href="#method.remove">remove</a><a href="#method.take">take</a><a href="#method.retain">retain</a></div><a class="sidebar-title" href="#implementations">Trait Implementations</a><div class="sidebar-links"><a href="#impl-Clone">Clone</a><a href="#impl-PartialEq">PartialEq</a><a href="#impl-Eq">Eq</a><a href="#impl-Debug">Debug</a><a href="#impl-FromIterator%3CT%3E">FromIterator<T></a><a href="#impl-Extend%3CT%3E">Extend<T></a><a href="#impl-Extend%3C%26%27a%20T%3E">Extend<&'a T></a><a href="#impl-Default">Default</a><a href="#impl-BitOr%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E">BitOr<&'b HashSet<T, S>></a><a href="#impl-BitAnd%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E">BitAnd<&'b HashSet<T, S>></a><a href="#impl-BitXor%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E">BitXor<&'b HashSet<T, S>></a><a href="#impl-Sub%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E">Sub<&'b HashSet<T, S>></a><a href="#impl-IntoIterator">IntoIterator</a></div><a class="sidebar-title" href="#synthetic-implementations">Auto Trait Implementations</a><div class="sidebar-links"><a href="#impl-Send">Send</a><a href="#impl-Sync">Sync</a></div></div><p class='location'><a href='../../index.html'>std</a>::<wbr><a href='../index.html'>collections</a>::<wbr><a href='index.html'>hash_set</a></p><script>window.sidebarCurrent = {name: 'HashSet', ty: 'struct', relpath: ''};</script><script defer src="sidebar-items.js"></script></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!"><img src="../../../brush.svg" width="18" alt="Pick another theme!"></button><div id="theme-choices"></div></div><script src="../../../theme.js"></script><nav class="sub"><form class="search-form js-only"><div class="search-container"><input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><a id="settings-menu" href="../../../settings.html"><img src="../../../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class='fqn'><span class='in-band'>Struct <a href='../../index.html'>std</a>::<wbr><a href='../index.html'>collections</a>::<wbr><a href='index.html'>hash_set</a>::<wbr><a class="struct" href=''>HashSet</a></span><span class='out-of-band'><span class='since' title='Stable since Rust version 1.0.0'>1.0.0</span><span id='render-detail'><a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class='inner'>−</span>]</a></span><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#121-123' title='goto source code'>[src]</a></span></h1><div class="docblock type-decl"><pre class='rust struct'>pub struct HashSet<T, S = <a class="struct" href="../../../std/collections/hash_map/struct.RandomState.html" title="struct std::collections::hash_map::RandomState">RandomState</a>> { /* fields omitted */ }</pre></div><div class='docblock'><p>A hash set implemented as a <code>HashMap</code> where the value is <code>()</code>.</p>
<p>As with the <a href="struct.HashMap.html"><code>HashMap</code></a> type, a <code>HashSet</code> requires that the elements
implement the <a href="../../std/cmp/trait.Eq.html"><code>Eq</code></a> and <a href="../../std/hash/trait.Hash.html"><code>Hash</code></a> traits. This can frequently be achieved by
using <code>#[derive(PartialEq, Eq, Hash)]</code>. If you implement these yourself,
it is important that the following property holds:</p>
<pre><code class="language-text">k1 == k2 -> hash(k1) == hash(k2)
</code></pre>
<p>In other words, if two keys are equal, their hashes must be equal.</p>
<p>It is a logic error for an item to be modified in such a way that the
item's hash, as determined by the <a href="../../std/hash/trait.Hash.html"><code>Hash</code></a> trait, or its equality, as
determined by the <a href="../../std/cmp/trait.Eq.html"><code>Eq</code></a> trait, changes while it is in the set. This is
normally only possible through <a href="../../std/cell/struct.Cell.html"><code>Cell</code></a>, <a href="../../std/cell/struct.RefCell.html"><code>RefCell</code></a>, global state, I/O, or
unsafe code.</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="comment">// Type inference lets us omit an explicit type signature (which</span>
<span class="comment">// would be `HashSet<String>` in this example).</span>
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">books</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="comment">// Add some books.</span>
<span class="ident">books</span>.<span class="ident">insert</span>(<span class="string">"A Dance With Dragons"</span>.<span class="ident">to_string</span>());
<span class="ident">books</span>.<span class="ident">insert</span>(<span class="string">"To Kill a Mockingbird"</span>.<span class="ident">to_string</span>());
<span class="ident">books</span>.<span class="ident">insert</span>(<span class="string">"The Odyssey"</span>.<span class="ident">to_string</span>());
<span class="ident">books</span>.<span class="ident">insert</span>(<span class="string">"The Great Gatsby"</span>.<span class="ident">to_string</span>());
<span class="comment">// Check for a specific one.</span>
<span class="kw">if</span> <span class="op">!</span><span class="ident">books</span>.<span class="ident">contains</span>(<span class="string">"The Winds of Winter"</span>) {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"We have {} books, but The Winds of Winter ain't one."</span>,
<span class="ident">books</span>.<span class="ident">len</span>());
}
<span class="comment">// Remove a book.</span>
<span class="ident">books</span>.<span class="ident">remove</span>(<span class="string">"The Odyssey"</span>);
<span class="comment">// Iterate over everything.</span>
<span class="kw">for</span> <span class="ident">book</span> <span class="kw">in</span> <span class="kw-2">&</span><span class="ident">books</span> {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{}"</span>, <span class="ident">book</span>);
}<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%2F%2F%20Type%20inference%20lets%20us%20omit%20an%20explicit%20type%20signature%20(which%0A%2F%2F%20would%20be%20%60HashSet%3CString%3E%60%20in%20this%20example).%0Alet%20mut%20books%20%3D%20HashSet%3A%3Anew()%3B%0A%0A%2F%2F%20Add%20some%20books.%0Abooks.insert(%22A%20Dance%20With%20Dragons%22.to_string())%3B%0Abooks.insert(%22To%20Kill%20a%20Mockingbird%22.to_string())%3B%0Abooks.insert(%22The%20Odyssey%22.to_string())%3B%0Abooks.insert(%22The%20Great%20Gatsby%22.to_string())%3B%0A%0A%2F%2F%20Check%20for%20a%20specific%20one.%0Aif%20!books.contains(%22The%20Winds%20of%20Winter%22)%20%7B%0A%20%20%20%20println!(%22We%20have%20%7B%7D%20books%2C%20but%20The%20Winds%20of%20Winter%20ain't%20one.%22%2C%0A%20%20%20%20%20%20%20%20%20%20%20%20%20books.len())%3B%0A%7D%0A%0A%2F%2F%20Remove%20a%20book.%0Abooks.remove(%22The%20Odyssey%22)%3B%0A%0A%2F%2F%20Iterate%20over%20everything.%0Afor%20book%20in%20%26books%20%7B%0A%20%20%20%20println!(%22%7B%7D%22%2C%20book)%3B%0A%7D%0A%7D">Run</a></pre>
<p>The easiest way to use <code>HashSet</code> with a custom type is to derive
<a href="../../std/cmp/trait.Eq.html"><code>Eq</code></a> and <a href="../../std/hash/trait.Hash.html"><code>Hash</code></a>. We must also derive <a href="../../std/cmp/trait.PartialEq.html"><code>PartialEq</code></a>, this will in the
future be implied by <a href="../../std/cmp/trait.Eq.html"><code>Eq</code></a>.</p>
<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="attribute">#[<span class="ident">derive</span>(<span class="ident">Hash</span>, <span class="ident">Eq</span>, <span class="ident">PartialEq</span>, <span class="ident">Debug</span>)]</span>
<span class="kw">struct</span> <span class="ident">Viking</span> {
<span class="ident">name</span>: <span class="ident">String</span>,
<span class="ident">power</span>: <span class="ident">usize</span>,
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">vikings</span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();
<span class="ident">vikings</span>.<span class="ident">insert</span>(<span class="ident">Viking</span> { <span class="ident">name</span>: <span class="string">"Einar"</span>.<span class="ident">to_string</span>(), <span class="ident">power</span>: <span class="number">9</span> });
<span class="ident">vikings</span>.<span class="ident">insert</span>(<span class="ident">Viking</span> { <span class="ident">name</span>: <span class="string">"Einar"</span>.<span class="ident">to_string</span>(), <span class="ident">power</span>: <span class="number">9</span> });
<span class="ident">vikings</span>.<span class="ident">insert</span>(<span class="ident">Viking</span> { <span class="ident">name</span>: <span class="string">"Olaf"</span>.<span class="ident">to_string</span>(), <span class="ident">power</span>: <span class="number">4</span> });
<span class="ident">vikings</span>.<span class="ident">insert</span>(<span class="ident">Viking</span> { <span class="ident">name</span>: <span class="string">"Harald"</span>.<span class="ident">to_string</span>(), <span class="ident">power</span>: <span class="number">8</span> });
<span class="comment">// Use derived implementation to print the vikings.</span>
<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="kw-2">&</span><span class="ident">vikings</span> {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{:?}"</span>, <span class="ident">x</span>);
}<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%23%5Bderive(Hash%2C%20Eq%2C%20PartialEq%2C%20Debug)%5D%0Astruct%20Viking%20%7B%0A%20%20%20%20name%3A%20String%2C%0A%20%20%20%20power%3A%20usize%2C%0A%7D%0A%0Alet%20mut%20vikings%20%3D%20HashSet%3A%3Anew()%3B%0A%0Avikings.insert(Viking%20%7B%20name%3A%20%22Einar%22.to_string()%2C%20power%3A%209%20%7D)%3B%0Avikings.insert(Viking%20%7B%20name%3A%20%22Einar%22.to_string()%2C%20power%3A%209%20%7D)%3B%0Avikings.insert(Viking%20%7B%20name%3A%20%22Olaf%22.to_string()%2C%20power%3A%204%20%7D)%3B%0Avikings.insert(Viking%20%7B%20name%3A%20%22Harald%22.to_string()%2C%20power%3A%208%20%7D)%3B%0A%0A%2F%2F%20Use%20derived%20implementation%20to%20print%20the%20vikings.%0Afor%20x%20in%20%26vikings%20%7B%0A%20%20%20%20println!(%22%7B%3A%3F%7D%22%2C%20x)%3B%0A%7D%0A%7D">Run</a></pre>
<p>A <code>HashSet</code> with fixed list of elements can be initialized from an array:</p>
<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">fn</span> <span class="ident">main</span>() {
<span class="kw">let</span> <span class="ident">viking_names</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw-2">&</span><span class="lifetime">'static</span> <span class="ident">str</span><span class="op">></span> <span class="op">=</span>
[ <span class="string">"Einar"</span>, <span class="string">"Olaf"</span>, <span class="string">"Harald"</span> ].<span class="ident">iter</span>().<span class="ident">cloned</span>().<span class="ident">collect</span>();
<span class="comment">// use the values stored in the set</span>
}<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Afn%20main()%20%7B%0A%20%20%20%20let%20viking_names%3A%20HashSet%3C%26'static%20str%3E%20%3D%0A%20%20%20%20%20%20%20%20%5B%20%22Einar%22%2C%20%22Olaf%22%2C%20%22Harald%22%20%5D.iter().cloned().collect()%3B%0A%20%20%20%20%2F%2F%20use%20the%20values%20stored%20in%20the%20set%0A%7D">Run</a></pre>
</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'><table class='table-display'><tbody><tr><td><code>impl<T: <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a>> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, <a class="struct" href="../../../std/collections/hash_map/struct.RandomState.html" title="struct std::collections::hash_map::RandomState">RandomState</a>></code><a href='#impl' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#125-160' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.new' class="method"><span id='new.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.new' class='fnname'>new</a>() -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, <a class="struct" href="../../../std/collections/hash_map/struct.RandomState.html" title="struct std::collections::hash_map::RandomState">RandomState</a>></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#139-141' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Creates an empty <code>HashSet</code>.</p>
<p>The hash set is initially created with a capacity of 0, so it will not allocate until it
is first inserted into.</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"><</span><span class="ident">i32</span><span class="op">></span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">new</span>();<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Alet%20set%3A%20HashSet%3Ci32%3E%20%3D%20HashSet%3A%3Anew()%3B%0A%7D">Run</a></pre>
</div><h4 id='method.with_capacity' class="method"><span id='with_capacity.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.with_capacity' class='fnname'>with_capacity</a>(capacity: <a class="primitive" href="../../primitive.usize.html">usize</a>) -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, <a class="struct" href="../../../std/collections/hash_map/struct.RandomState.html" title="struct std::collections::hash_map::RandomState">RandomState</a>></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#157-159' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Creates an empty <code>HashSet</code> with the specified capacity.</p>
<p>The hash set will be able to hold at least <code>capacity</code> elements without
reallocating. If <code>capacity</code> is 0, the hash set will not allocate.</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="ident">set</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="ident">i32</span><span class="op">></span> <span class="op">=</span> <span class="ident">HashSet</span>::<span class="ident">with_capacity</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">>=</span> <span class="number">10</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Alet%20set%3A%20HashSet%3Ci32%3E%20%3D%20HashSet%3A%3Awith_capacity(10)%3B%0Aassert!(set.capacity()%20%3E%3D%2010)%3B%0A%7D">Run</a></pre>
</div></div><h3 id='impl-1' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T, S> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></code><a href='#impl-1' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#162-765' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.with_hasher' class="method"><span id='with_hasher.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.with_hasher' class='fnname'>with_hasher</a>(hasher: S) -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.7.0'>1.7.0</div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#188-190' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Creates a new empty hash set which will use the given hasher to hash
keys.</p>
<p>The hash set is also created with the default initial capacity.</p>
<p>Warning: <code>hasher</code> is normally randomly generated, and
is designed to allow <code>HashSet</code>s to be resistant to attacks that
cause many collisions and very poor performance. Setting it
manually using this function can expose a DoS attack vector.</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">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">s</span> <span class="op">=</span> <span class="ident">RandomState</span>::<span class="ident">new</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_hasher</span>(<span class="ident">s</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">2</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Ause%20std%3A%3Acollections%3A%3Ahash_map%3A%3ARandomState%3B%0A%0Alet%20s%20%3D%20RandomState%3A%3Anew()%3B%0Alet%20mut%20set%20%3D%20HashSet%3A%3Awith_hasher(s)%3B%0Aset.insert(2)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.with_capacity_and_hasher' class="method"><span id='with_capacity_and_hasher.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.with_capacity_and_hasher' class='fnname'>with_capacity_and_hasher</a>(capacity: <a class="primitive" href="../../primitive.usize.html">usize</a>, hasher: S) -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.7.0'>1.7.0</div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#215-217' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Creates an empty <code>HashSet</code> with with the specified capacity, using
<code>hasher</code> to hash the keys.</p>
<p>The hash set will be able to hold at least <code>capacity</code> elements without
reallocating. If <code>capacity</code> is 0, the hash set will not allocate.</p>
<p>Warning: <code>hasher</code> is normally randomly generated, and
is designed to allow <code>HashSet</code>s to be resistant to attacks that
cause many collisions and very poor performance. Setting it
manually using this function can expose a DoS attack vector.</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">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">s</span> <span class="op">=</span> <span class="ident">RandomState</span>::<span class="ident">new</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_and_hasher</span>(<span class="number">10</span>, <span class="ident">s</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="number">1</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Ause%20std%3A%3Acollections%3A%3Ahash_map%3A%3ARandomState%3B%0A%0Alet%20s%20%3D%20RandomState%3A%3Anew()%3B%0Alet%20mut%20set%20%3D%20HashSet%3A%3Awith_capacity_and_hasher(10%2C%20s)%3B%0Aset.insert(1)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.hasher' class="method"><div class="important-traits"><div class='tooltip'>ⓘ<span class='tooltiptext'>Important traits for <a class="primitive" href="../../primitive.reference.html">&'a mut </a>I</span></div><div class="content hidden"><h3 class="important">Important traits for <a class="primitive" href="../../primitive.reference.html">&'a mut </a>I</h3><code class="content"><span class="where fmt-newline">impl<'a, I> <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a> for <a class="primitive" href="../../primitive.reference.html">&'a mut </a>I <span class="where fmt-newline">where<br> I: <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a> + ?<a class="trait" href="../../../std/marker/trait.Sized.html" title="trait std::marker::Sized">Sized</a>, </span></span><span class="where fmt-newline"> type <a href='../../../std/iter/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <I as <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a>>::<a class="type" href="../../../std/iter/trait.Iterator.html#associatedtype.Item" title="type std::iter::Iterator::Item">Item</a>;</span><span class="where fmt-newline">impl<'a, R: <a class="trait" href="../../../std/io/trait.Read.html" title="trait std::io::Read">Read</a> + ?<a class="trait" href="../../../std/marker/trait.Sized.html" title="trait std::marker::Sized">Sized</a>> <a class="trait" href="../../../std/io/trait.Read.html" title="trait std::io::Read">Read</a> for <a class="primitive" href="../../primitive.reference.html">&'a mut </a>R</span><span class="where fmt-newline">impl<'a, W: <a class="trait" href="../../../std/io/trait.Write.html" title="trait std::io::Write">Write</a> + ?<a class="trait" href="../../../std/marker/trait.Sized.html" title="trait std::marker::Sized">Sized</a>> <a class="trait" href="../../../std/io/trait.Write.html" title="trait std::io::Write">Write</a> for <a class="primitive" href="../../primitive.reference.html">&'a mut </a>W</span></code></div></div><span id='hasher.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.hasher' class='fnname'>hasher</a>(&self) -> <a class="primitive" href="../../primitive.reference.html">&</a>S</code></span></td><td><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='../../../src/std/collections/hash/set.rs.html#234-236' title='goto source code'>[src]</a></td></tr></tbody></table></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-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">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"><</span><span class="ident">i32</span><span class="op">></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">&</span><span class="ident">RandomState</span> <span class="op">=</span> <span class="ident">set</span>.<span class="ident">hasher</span>();<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Ause%20std%3A%3Acollections%3A%3Ahash_map%3A%3ARandomState%3B%0A%0Alet%20hasher%20%3D%20RandomState%3A%3Anew()%3B%0Alet%20set%3A%20HashSet%3Ci32%3E%20%3D%20HashSet%3A%3Awith_hasher(hasher)%3B%0Alet%20hasher%3A%20%26RandomState%20%3D%20set.hasher()%3B%0A%7D">Run</a></pre>
</div><h4 id='method.capacity' class="method"><span id='capacity.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.capacity' class='fnname'>capacity</a>(&self) -> <a class="primitive" href="../../primitive.usize.html">usize</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#249-251' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Returns the number of elements the set can hold without reallocating.</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">set</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="ident">i32</span><span class="op">></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">>=</span> <span class="number">100</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Alet%20set%3A%20HashSet%3Ci32%3E%20%3D%20HashSet%3A%3Awith_capacity(100)%3B%0Aassert!(set.capacity()%20%3E%3D%20100)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.reserve' class="method"><span id='reserve.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.reserve' class='fnname'>reserve</a>(&mut self, additional: <a class="primitive" href="../../primitive.usize.html">usize</a>)</code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#270-272' title='goto source code'>[src]</a></td></tr></tbody></table></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-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="kw-2">mut</span> <span class="ident">set</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="ident">i32</span><span class="op">></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">>=</span> <span class="number">10</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Alet%20mut%20set%3A%20HashSet%3Ci32%3E%20%3D%20HashSet%3A%3Anew()%3B%0Aset.reserve(10)%3B%0Aassert!(set.capacity()%20%3E%3D%2010)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.shrink_to_fit' class="method"><span id='shrink_to_fit.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.shrink_to_fit' class='fnname'>shrink_to_fit</a>(&mut self)</code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#291-293' title='goto source code'>[src]</a></td></tr></tbody></table></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-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="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">>=</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">>=</span> <span class="number">2</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20mut%20set%20%3D%20HashSet%3A%3Awith_capacity(100)%3B%0Aset.insert(1)%3B%0Aset.insert(2)%3B%0Aassert!(set.capacity()%20%3E%3D%20100)%3B%0Aset.shrink_to_fit()%3B%0Aassert!(set.capacity()%20%3E%3D%202)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.shrink_to' class="method"><span id='shrink_to.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.shrink_to' class='fnname'>shrink_to</a>(&mut self, min_capacity: <a class="primitive" href="../../primitive.usize.html">usize</a>)</code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#319-321' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='stability'><div class='stab unstable'><details><summary><span class=microscope>🔬</span> This is a nightly-only experimental API. (<code>shrink_to</code>)</summary><p>new API</p>
</details></div></div><div class='docblock'><p>Shrinks the capacity of the set with a lower limit. It will drop
down no lower than the supplied limit while maintaining the internal rules
and possibly leaving some space in accordance with the resize policy.</p>
<p>Panics if the current capacity is smaller than the supplied
minimum capacity.</p>
<h1 id="examples-9" class="section-header"><a href="#examples-9">Examples</a></h1>
<pre class="rust rust-example-rendered">
<span class="attribute">#![<span class="ident">feature</span>(<span class="ident">shrink_to</span>)]</span>
<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">>=</span> <span class="number">100</span>);
<span class="ident">set</span>.<span class="ident">shrink_to</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">>=</span> <span class="number">10</span>);
<span class="ident">set</span>.<span class="ident">shrink_to</span>(<span class="number">0</span>);
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">set</span>.<span class="ident">capacity</span>() <span class="op">>=</span> <span class="number">2</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0A%23!%5Bfeature(shrink_to)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20mut%20set%20%3D%20HashSet%3A%3Awith_capacity(100)%3B%0Aset.insert(1)%3B%0Aset.insert(2)%3B%0Aassert!(set.capacity()%20%3E%3D%20100)%3B%0Aset.shrink_to(10)%3B%0Aassert!(set.capacity()%20%3E%3D%2010)%3B%0Aset.shrink_to(0)%3B%0Aassert!(set.capacity()%20%3E%3D%202)%3B%0A%7D&version=nightly">Run</a></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="../../../std/collections/hash_set/struct.Iter.html" title="struct std::collections::hash_set::Iter">Iter</a><'a, K></span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="../../../std/collections/hash_set/struct.Iter.html" title="struct std::collections::hash_set::Iter">Iter</a><'a, K></h3><code class="content"><span class="where fmt-newline">impl<'a, K> <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a> for <a class="struct" href="../../../std/collections/hash_set/struct.Iter.html" title="struct std::collections::hash_set::Iter">Iter</a><'a, K></span><span class="where fmt-newline"> type <a href='../../../std/iter/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="../../primitive.reference.html">&'a </a>K;</span></code></div></div><span id='iter.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.iter' class='fnname'>iter</a>(&self) -> <a class="struct" href="../../../std/collections/hash_set/struct.Iter.html" title="struct std::collections::hash_set::Iter">Iter</a><T></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#340-342' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>An iterator visiting all elements in arbitrary order.
The iterator element type is <code>&'a T</code>.</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">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">"a"</span>);
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="string">"b"</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">"{}"</span>, <span class="ident">x</span>);
}<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Alet%20mut%20set%20%3D%20HashSet%3A%3Anew()%3B%0Aset.insert(%22a%22)%3B%0Aset.insert(%22b%22)%3B%0A%0A%2F%2F%20Will%20print%20in%20an%20arbitrary%20order.%0Afor%20x%20in%20set.iter()%20%7B%0A%20%20%20%20println!(%22%7B%7D%22%2C%20x)%3B%0A%7D%0A%7D">Run</a></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="../../../std/collections/hash_set/struct.Difference.html" title="struct std::collections::hash_set::Difference">Difference</a><'a, T, S></span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="../../../std/collections/hash_set/struct.Difference.html" title="struct std::collections::hash_set::Difference">Difference</a><'a, T, S></h3><code class="content"><span class="where fmt-newline">impl<'a, T, S> <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a> for <a class="struct" href="../../../std/collections/hash_set/struct.Difference.html" title="struct std::collections::hash_set::Difference">Difference</a><'a, T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></span><span class="where fmt-newline"> type <a href='../../../std/iter/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="../../primitive.reference.html">&'a </a>T;</span></code></div></div><span id='difference.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.difference' class='fnname'>difference</a><'a>(<br> &'a self, <br> other: &'a <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S><br>) -> <a class="struct" href="../../../std/collections/hash_set/struct.Difference.html" title="struct std::collections::hash_set::Difference">Difference</a><'a, T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#368-373' title='goto source code'>[src]</a></td></tr></tbody></table></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-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="ident">a</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></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"><</span><span class="kw">_</span><span class="op">></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">&</span><span class="ident">b</span>) {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{}"</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"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="ident">a</span>.<span class="ident">difference</span>(<span class="kw-2">&</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"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">difference</span>(<span class="kw-2">&</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>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Alet%20a%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%2C%203%5D.iter().cloned().collect()%3B%0Alet%20b%3A%20HashSet%3C_%3E%20%3D%20%5B4%2C%202%2C%203%2C%204%5D.iter().cloned().collect()%3B%0A%0A%2F%2F%20Can%20be%20seen%20as%20%60a%20-%20b%60.%0Afor%20x%20in%20a.difference(%26b)%20%7B%0A%20%20%20%20println!(%22%7B%7D%22%2C%20x)%3B%20%2F%2F%20Print%201%0A%7D%0A%0Alet%20diff%3A%20HashSet%3C_%3E%20%3D%20a.difference(%26b).collect()%3B%0Aassert_eq!(diff%2C%20%5B1%5D.iter().collect())%3B%0A%0A%2F%2F%20Note%20that%20difference%20is%20not%20symmetric%2C%0A%2F%2F%20and%20%60b%20-%20a%60%20means%20something%20else%3A%0Alet%20diff%3A%20HashSet%3C_%3E%20%3D%20b.difference(%26a).collect()%3B%0Aassert_eq!(diff%2C%20%5B4%5D.iter().collect())%3B%0A%7D">Run</a></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="../../../std/collections/hash_set/struct.SymmetricDifference.html" title="struct std::collections::hash_set::SymmetricDifference">SymmetricDifference</a><'a, T, S></span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="../../../std/collections/hash_set/struct.SymmetricDifference.html" title="struct std::collections::hash_set::SymmetricDifference">SymmetricDifference</a><'a, T, S></h3><code class="content"><span class="where fmt-newline">impl<'a, T, S> <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a> for <a class="struct" href="../../../std/collections/hash_set/struct.SymmetricDifference.html" title="struct std::collections::hash_set::SymmetricDifference">SymmetricDifference</a><'a, T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></span><span class="where fmt-newline"> type <a href='../../../std/iter/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="../../primitive.reference.html">&'a </a>T;</span></code></div></div><span id='symmetric_difference.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.symmetric_difference' class='fnname'>symmetric_difference</a><'a>(<br> &'a self, <br> other: &'a <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S><br>) -> <a class="struct" href="../../../std/collections/hash_set/struct.SymmetricDifference.html" title="struct std::collections::hash_set::SymmetricDifference">SymmetricDifference</a><'a, T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#397-401' title='goto source code'>[src]</a></td></tr></tbody></table></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-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="ident">a</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></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"><</span><span class="kw">_</span><span class="op">></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">&</span><span class="ident">b</span>) {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{}"</span>, <span class="ident">x</span>);
}
<span class="kw">let</span> <span class="ident">diff1</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="ident">a</span>.<span class="ident">symmetric_difference</span>(<span class="kw-2">&</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"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="ident">b</span>.<span class="ident">symmetric_difference</span>(<span class="kw-2">&</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>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Alet%20a%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%2C%203%5D.iter().cloned().collect()%3B%0Alet%20b%3A%20HashSet%3C_%3E%20%3D%20%5B4%2C%202%2C%203%2C%204%5D.iter().cloned().collect()%3B%0A%0A%2F%2F%20Print%201%2C%204%20in%20arbitrary%20order.%0Afor%20x%20in%20a.symmetric_difference(%26b)%20%7B%0A%20%20%20%20println!(%22%7B%7D%22%2C%20x)%3B%0A%7D%0A%0Alet%20diff1%3A%20HashSet%3C_%3E%20%3D%20a.symmetric_difference(%26b).collect()%3B%0Alet%20diff2%3A%20HashSet%3C_%3E%20%3D%20b.symmetric_difference(%26a).collect()%3B%0A%0Aassert_eq!(diff1%2C%20diff2)%3B%0Aassert_eq!(diff1%2C%20%5B1%2C%204%5D.iter().collect())%3B%0A%7D">Run</a></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="../../../std/collections/hash_set/struct.Intersection.html" title="struct std::collections::hash_set::Intersection">Intersection</a><'a, T, S></span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="../../../std/collections/hash_set/struct.Intersection.html" title="struct std::collections::hash_set::Intersection">Intersection</a><'a, T, S></h3><code class="content"><span class="where fmt-newline">impl<'a, T, S> <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a> for <a class="struct" href="../../../std/collections/hash_set/struct.Intersection.html" title="struct std::collections::hash_set::Intersection">Intersection</a><'a, T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></span><span class="where fmt-newline"> type <a href='../../../std/iter/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="../../primitive.reference.html">&'a </a>T;</span></code></div></div><span id='intersection.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.intersection' class='fnname'>intersection</a><'a>(<br> &'a self, <br> other: &'a <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S><br>) -> <a class="struct" href="../../../std/collections/hash_set/struct.Intersection.html" title="struct std::collections::hash_set::Intersection">Intersection</a><'a, T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#422-427' title='goto source code'>[src]</a></td></tr></tbody></table></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-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">a</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></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"><</span><span class="kw">_</span><span class="op">></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">&</span><span class="ident">b</span>) {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{}"</span>, <span class="ident">x</span>);
}
<span class="kw">let</span> <span class="ident">intersection</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="ident">a</span>.<span class="ident">intersection</span>(<span class="kw-2">&</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>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Alet%20a%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%2C%203%5D.iter().cloned().collect()%3B%0Alet%20b%3A%20HashSet%3C_%3E%20%3D%20%5B4%2C%202%2C%203%2C%204%5D.iter().cloned().collect()%3B%0A%0A%2F%2F%20Print%202%2C%203%20in%20arbitrary%20order.%0Afor%20x%20in%20a.intersection(%26b)%20%7B%0A%20%20%20%20println!(%22%7B%7D%22%2C%20x)%3B%0A%7D%0A%0Alet%20intersection%3A%20HashSet%3C_%3E%20%3D%20a.intersection(%26b).collect()%3B%0Aassert_eq!(intersection%2C%20%5B2%2C%203%5D.iter().collect())%3B%0A%7D">Run</a></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="../../../std/collections/hash_set/struct.Union.html" title="struct std::collections::hash_set::Union">Union</a><'a, T, S></span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="../../../std/collections/hash_set/struct.Union.html" title="struct std::collections::hash_set::Union">Union</a><'a, T, S></h3><code class="content"><span class="where fmt-newline">impl<'a, T, S> <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a> for <a class="struct" href="../../../std/collections/hash_set/struct.Union.html" title="struct std::collections::hash_set::Union">Union</a><'a, T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></span><span class="where fmt-newline"> type <a href='../../../std/iter/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="../../primitive.reference.html">&'a </a>T;</span></code></div></div><span id='union.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.union' class='fnname'>union</a><'a>(&'a self, other: &'a <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>) -> <a class="struct" href="../../../std/collections/hash_set/struct.Union.html" title="struct std::collections::hash_set::Union">Union</a><'a, T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#448-450' title='goto source code'>[src]</a></td></tr></tbody></table></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-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">a</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></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"><</span><span class="kw">_</span><span class="op">></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">&</span><span class="ident">b</span>) {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{}"</span>, <span class="ident">x</span>);
}
<span class="kw">let</span> <span class="ident">union</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="ident">a</span>.<span class="ident">union</span>(<span class="kw-2">&</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>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Alet%20a%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%2C%203%5D.iter().cloned().collect()%3B%0Alet%20b%3A%20HashSet%3C_%3E%20%3D%20%5B4%2C%202%2C%203%2C%204%5D.iter().cloned().collect()%3B%0A%0A%2F%2F%20Print%201%2C%202%2C%203%2C%204%20in%20arbitrary%20order.%0Afor%20x%20in%20a.union(%26b)%20%7B%0A%20%20%20%20println!(%22%7B%7D%22%2C%20x)%3B%0A%7D%0A%0Alet%20union%3A%20HashSet%3C_%3E%20%3D%20a.union(%26b).collect()%3B%0Aassert_eq!(union%2C%20%5B1%2C%202%2C%203%2C%204%5D.iter().collect())%3B%0A%7D">Run</a></pre>
</div><h4 id='method.len' class="method"><span id='len.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.len' class='fnname'>len</a>(&self) -> <a class="primitive" href="../../primitive.usize.html">usize</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#465-467' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Returns the number of elements in the set.</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="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>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20mut%20v%20%3D%20HashSet%3A%3Anew()%3B%0Aassert_eq!(v.len()%2C%200)%3B%0Av.insert(1)%3B%0Aassert_eq!(v.len()%2C%201)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.is_empty' class="method"><span id='is_empty.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.is_empty' class='fnname'>is_empty</a>(&self) -> <a class="primitive" href="../../primitive.bool.html">bool</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#482-484' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Returns true if the set contains no elements.</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="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>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20mut%20v%20%3D%20HashSet%3A%3Anew()%3B%0Aassert!(v.is_empty())%3B%0Av.insert(1)%3B%0Aassert!(!v.is_empty())%3B%0A%7D">Run</a></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="../../../std/collections/hash_set/struct.Drain.html" title="struct std::collections::hash_set::Drain">Drain</a><'a, K></span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="../../../std/collections/hash_set/struct.Drain.html" title="struct std::collections::hash_set::Drain">Drain</a><'a, K></h3><code class="content"><span class="where fmt-newline">impl<'a, K> <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a> for <a class="struct" href="../../../std/collections/hash_set/struct.Drain.html" title="struct std::collections::hash_set::Drain">Drain</a><'a, K></span><span class="where fmt-newline"> type <a href='../../../std/iter/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = K;</span></code></div></div><span id='drain.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.drain' class='fnname'>drain</a>(&mut self) -> <a class="struct" href="../../../std/collections/hash_set/struct.Drain.html" title="struct std::collections::hash_set::Drain">Drain</a><T></code></span></td><td><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='../../../src/std/collections/hash/set.rs.html#505-507' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Clears the set, returning all elements in an iterator.</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="kw-2">mut</span> <span class="ident">set</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></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">"{}"</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>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20mut%20set%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%2C%203%5D.iter().cloned().collect()%3B%0Aassert!(!set.is_empty())%3B%0A%0A%2F%2F%20print%201%2C%202%2C%203%20in%20an%20arbitrary%20order%0Afor%20i%20in%20set.drain()%20%7B%0A%20%20%20%20println!(%22%7B%7D%22%2C%20i)%3B%0A%7D%0A%0Aassert!(set.is_empty())%3B%0A%7D">Run</a></pre>
</div><h4 id='method.clear' class="method"><span id='clear.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.clear' class='fnname'>clear</a>(&mut self)</code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#522-524' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Clears the set, removing all values.</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">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>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20mut%20v%20%3D%20HashSet%3A%3Anew()%3B%0Av.insert(1)%3B%0Av.clear()%3B%0Aassert!(v.is_empty())%3B%0A%7D">Run</a></pre>
</div><h4 id='method.contains' class="method"><span id='contains.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.contains' class='fnname'>contains</a><Q: ?<a class="trait" href="../../../std/marker/trait.Sized.html" title="trait std::marker::Sized">Sized</a>>(&self, value: <a class="primitive" href="../../primitive.reference.html">&</a>Q) -> <a class="primitive" href="../../primitive.bool.html">bool</a> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/borrow/trait.Borrow.html" title="trait std::borrow::Borrow">Borrow</a><Q>,<br> Q: <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a>, </span></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#545-550' title='goto source code'>[src]</a></td></tr></tbody></table></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-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="ident">set</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></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">&</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">&</span><span class="number">4</span>), <span class="bool-val">false</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20set%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%2C%203%5D.iter().cloned().collect()%3B%0Aassert_eq!(set.contains(%261)%2C%20true)%3B%0Aassert_eq!(set.contains(%264)%2C%20false)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.get' class="method"><span id='get.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.get' class='fnname'>get</a><Q: ?<a class="trait" href="../../../std/marker/trait.Sized.html" title="trait std::marker::Sized">Sized</a>>(&self, value: <a class="primitive" href="../../primitive.reference.html">&</a>Q) -> <a class="enum" href="../../../std/option/enum.Option.html" title="enum std::option::Option">Option</a><<a class="primitive" href="../../primitive.reference.html">&</a>T> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/borrow/trait.Borrow.html" title="trait std::borrow::Borrow">Borrow</a><Q>,<br> Q: <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a>, </span></code></span></td><td><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='../../../src/std/collections/hash/set.rs.html#571-576' title='goto source code'>[src]</a></td></tr></tbody></table></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-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="ident">set</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></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">&</span><span class="number">2</span>), <span class="prelude-val">Some</span>(<span class="kw-2">&</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">&</span><span class="number">4</span>), <span class="prelude-val">None</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20set%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%2C%203%5D.iter().cloned().collect()%3B%0Aassert_eq!(set.get(%262)%2C%20Some(%262))%3B%0Aassert_eq!(set.get(%264)%2C%20None)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.is_disjoint' class="method"><span id='is_disjoint.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.is_disjoint' class='fnname'>is_disjoint</a>(&self, other: &<a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>) -> <a class="primitive" href="../../primitive.bool.html">bool</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#596-598' title='goto source code'>[src]</a></td></tr></tbody></table></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-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="ident">a</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></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">&</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">&</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">&</span><span class="ident">b</span>), <span class="bool-val">false</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20a%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%2C%203%5D.iter().cloned().collect()%3B%0Alet%20mut%20b%20%3D%20HashSet%3A%3Anew()%3B%0A%0Aassert_eq!(a.is_disjoint(%26b)%2C%20true)%3B%0Ab.insert(4)%3B%0Aassert_eq!(a.is_disjoint(%26b)%2C%20true)%3B%0Ab.insert(1)%3B%0Aassert_eq!(a.is_disjoint(%26b)%2C%20false)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.is_subset' class="method"><span id='is_subset.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.is_subset' class='fnname'>is_subset</a>(&self, other: &<a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>) -> <a class="primitive" href="../../primitive.bool.html">bool</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#618-620' title='goto source code'>[src]</a></td></tr></tbody></table></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-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">sup</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></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">&</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">&</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">&</span><span class="ident">sup</span>), <span class="bool-val">false</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20sup%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%2C%203%5D.iter().cloned().collect()%3B%0Alet%20mut%20set%20%3D%20HashSet%3A%3Anew()%3B%0A%0Aassert_eq!(set.is_subset(%26sup)%2C%20true)%3B%0Aset.insert(2)%3B%0Aassert_eq!(set.is_subset(%26sup)%2C%20true)%3B%0Aset.insert(4)%3B%0Aassert_eq!(set.is_subset(%26sup)%2C%20false)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.is_superset' class="method"><span id='is_superset.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.is_superset' class='fnname'>is_superset</a>(&self, other: &<a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>) -> <a class="primitive" href="../../primitive.bool.html">bool</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#644-646' title='goto source code'>[src]</a></td></tr></tbody></table></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-23" class="section-header"><a href="#examples-23">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"><</span><span class="kw">_</span><span class="op">></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">&</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">&</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">&</span><span class="ident">sub</span>), <span class="bool-val">true</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20sub%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%5D.iter().cloned().collect()%3B%0Alet%20mut%20set%20%3D%20HashSet%3A%3Anew()%3B%0A%0Aassert_eq!(set.is_superset(%26sub)%2C%20false)%3B%0A%0Aset.insert(0)%3B%0Aset.insert(1)%3B%0Aassert_eq!(set.is_superset(%26sub)%2C%20false)%3B%0A%0Aset.insert(2)%3B%0Aassert_eq!(set.is_superset(%26sub)%2C%20true)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.insert' class="method"><span id='insert.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.insert' class='fnname'>insert</a>(&mut self, value: T) -> <a class="primitive" href="../../primitive.bool.html">bool</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#666-668' title='goto source code'>[src]</a></td></tr></tbody></table></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-24" class="section-header"><a href="#examples-24">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>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20mut%20set%20%3D%20HashSet%3A%3Anew()%3B%0A%0Aassert_eq!(set.insert(2)%2C%20true)%3B%0Aassert_eq!(set.insert(2)%2C%20false)%3B%0Aassert_eq!(set.len()%2C%201)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.replace' class="method"><span id='replace.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.replace' class='fnname'>replace</a>(&mut self, value: T) -> <a class="enum" href="../../../std/option/enum.Option.html" title="enum std::option::Option">Option</a><T></code></span></td><td><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='../../../src/std/collections/hash/set.rs.html#686-688' title='goto source code'>[src]</a></td></tr></tbody></table></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-25" class="section-header"><a href="#examples-25">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"><</span><span class="ident">i32</span><span class="op">></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">&</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">&</span>[][..]).<span class="ident">unwrap</span>().<span class="ident">capacity</span>(), <span class="number">10</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20mut%20set%20%3D%20HashSet%3A%3Anew()%3B%0Aset.insert(Vec%3A%3A%3Ci32%3E%3A%3Anew())%3B%0A%0Aassert_eq!(set.get(%26%5B%5D%5B..%5D).unwrap().capacity()%2C%200)%3B%0Aset.replace(Vec%3A%3Awith_capacity(10))%3B%0Aassert_eq!(set.get(%26%5B%5D%5B..%5D).unwrap().capacity()%2C%2010)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.remove' class="method"><span id='remove.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.remove' class='fnname'>remove</a><Q: ?<a class="trait" href="../../../std/marker/trait.Sized.html" title="trait std::marker::Sized">Sized</a>>(&mut self, value: <a class="primitive" href="../../primitive.reference.html">&</a>Q) -> <a class="primitive" href="../../primitive.bool.html">bool</a> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/borrow/trait.Borrow.html" title="trait std::borrow::Borrow">Borrow</a><Q>,<br> Q: <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a>, </span></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#712-717' title='goto source code'>[src]</a></td></tr></tbody></table></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-26" class="section-header"><a href="#examples-26">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">&</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">&</span><span class="number">2</span>), <span class="bool-val">false</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20mut%20set%20%3D%20HashSet%3A%3Anew()%3B%0A%0Aset.insert(2)%3B%0Aassert_eq!(set.remove(%262)%2C%20true)%3B%0Aassert_eq!(set.remove(%262)%2C%20false)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.take' class="method"><span id='take.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.take' class='fnname'>take</a><Q: ?<a class="trait" href="../../../std/marker/trait.Sized.html" title="trait std::marker::Sized">Sized</a>>(&mut self, value: <a class="primitive" href="../../primitive.reference.html">&</a>Q) -> <a class="enum" href="../../../std/option/enum.Option.html" title="enum std::option::Option">Option</a><T> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/borrow/trait.Borrow.html" title="trait std::borrow::Borrow">Borrow</a><Q>,<br> Q: <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a>, </span></code></span></td><td><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='../../../src/std/collections/hash/set.rs.html#738-743' title='goto source code'>[src]</a></td></tr></tbody></table></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-27" class="section-header"><a href="#examples-27">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"><</span><span class="kw">_</span><span class="op">></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">&</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">&</span><span class="number">2</span>), <span class="prelude-val">None</span>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20mut%20set%3A%20HashSet%3C_%3E%20%3D%20%5B1%2C%202%2C%203%5D.iter().cloned().collect()%3B%0Aassert_eq!(set.take(%262)%2C%20Some(2))%3B%0Aassert_eq!(set.take(%262)%2C%20None)%3B%0A%7D">Run</a></pre>
</div><h4 id='method.retain' class="method"><span id='retain.v' class='invisible'><table class='table-display'><tbody><tr><td><code>pub fn <a href='#method.retain' class='fnname'>retain</a><F>(&mut self, f: F) <span class="where fmt-newline">where<br> F: <a class="trait" href="../../../std/ops/trait.FnMut.html" title="trait std::ops::FnMut">FnMut</a>(<a class="primitive" href="../../primitive.reference.html">&</a>T) -> <a class="primitive" href="../../primitive.bool.html">bool</a>, </span></code></span></td><td><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='../../../src/std/collections/hash/set.rs.html#760-764' title='goto source code'>[src]</a></td></tr></tbody></table></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(&e)</code> returns <code>false</code>.</p>
<h1 id="examples-28" class="section-header"><a href="#examples-28">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"><</span><span class="ident">i32</span><span class="op">></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">&</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>);<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20xs%20%3D%20%5B1%2C2%2C3%2C4%2C5%2C6%5D%3B%0Alet%20mut%20set%3A%20HashSet%3Ci32%3E%20%3D%20xs.iter().cloned().collect()%3B%0Aset.retain(%7C%26k%7C%20k%20%25%202%20%3D%3D%200)%3B%0Aassert_eq!(set.len()%2C%203)%3B%0A%7D">Run</a></pre>
</div></div>
<h2 id='implementations' class='small-section-header'>
Trait Implementations<a href='#implementations' class='anchor'></a>
</h2>
<div id='implementations-list'><h3 id='impl-Clone' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T: <a class="trait" href="../../../std/clone/trait.Clone.html" title="trait std::clone::Clone">Clone</a>, S: <a class="trait" href="../../../std/clone/trait.Clone.html" title="trait std::clone::Clone">Clone</a>> <a class="trait" href="../../../std/clone/trait.Clone.html" title="trait std::clone::Clone">Clone</a> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code><a href='#impl-Clone' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#119' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.clone' class="method"><span id='clone.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/clone/trait.Clone.html#tymethod.clone' class='fnname'>clone</a>(&self) -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#119' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Returns a copy of the value. <a href="../../../std/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'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/clone/trait.Clone.html#method.clone_from' class='fnname'>clone_from</a>(&mut self, source: <a class="primitive" href="../../primitive.reference.html">&</a>Self)</code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/core/clone.rs.html#130-132' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Performs copy-assignment from <code>source</code>. <a href="../../../std/clone/trait.Clone.html#method.clone_from">Read more</a></p>
</div></div><h3 id='impl-PartialEq' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T, S> <a class="trait" href="../../../std/cmp/trait.PartialEq.html" title="trait std::cmp::PartialEq">PartialEq</a> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></code><a href='#impl-PartialEq' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#768-779' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.eq' class="method"><span id='eq.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/cmp/trait.PartialEq.html#tymethod.eq' class='fnname'>eq</a>(&self, other: &<a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>) -> <a class="primitive" href="../../primitive.bool.html">bool</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#772-778' title='goto source code'>[src]</a></td></tr></tbody></table></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="../../../std/cmp/trait.PartialEq.html#tymethod.eq">Read more</a></p>
</div><h4 id='method.ne' class="method"><span id='ne.v' class='invisible'><table class='table-display'><tbody><tr><td><code><div class="docblock attributes">#[must_use]
</div>fn <a href='../../../std/cmp/trait.PartialEq.html#method.ne' class='fnname'>ne</a>(&self, other: <a class="primitive" href="../../primitive.reference.html">&</a>Rhs) -> <a class="primitive" href="../../primitive.bool.html">bool</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/core/cmp.rs.html#123' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>This method tests for <code>!=</code>.</p>
</div></div><h3 id='impl-Eq' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T, S> <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></code><a href='#impl-Eq' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#782-786' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'></div><h3 id='impl-Debug' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T, S> <a class="trait" href="../../../std/fmt/trait.Debug.html" title="trait std::fmt::Debug">Debug</a> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/fmt/trait.Debug.html" title="trait std::fmt::Debug">Debug</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></code><a href='#impl-Debug' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#789-796' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.fmt' class="method"><span id='fmt.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/fmt/trait.Debug.html#tymethod.fmt' class='fnname'>fmt</a>(&self, f: &mut <a class="struct" href="../../../std/fmt/struct.Formatter.html" title="struct std::fmt::Formatter">Formatter</a>) -> <a class="type" href="../../../std/fmt/type.Result.html" title="type std::fmt::Result">Result</a></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#793-795' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Formats the value using the given formatter. <a href="../../../std/fmt/trait.Debug.html#tymethod.fmt">Read more</a></p>
</div></div><h3 id='impl-FromIterator%3CT%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T, S> <a class="trait" href="../../../std/iter/trait.FromIterator.html" title="trait std::iter::FromIterator">FromIterator</a><T> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a> + <a class="trait" href="../../../std/default/trait.Default.html" title="trait std::default::Default">Default</a>, </span></code><a href='#impl-FromIterator%3CT%3E' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#799-808' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.from_iter' class="method"><span id='from_iter.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/iter/trait.FromIterator.html#tymethod.from_iter' class='fnname'>from_iter</a><I: <a class="trait" href="../../../std/iter/trait.IntoIterator.html" title="trait std::iter::IntoIterator">IntoIterator</a><Item = T>>(iter: I) -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#803-807' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Creates a value from an iterator. <a href="../../../std/iter/trait.FromIterator.html#tymethod.from_iter">Read more</a></p>
</div></div><h3 id='impl-Extend%3CT%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T, S> <a class="trait" href="../../../std/iter/trait.Extend.html" title="trait std::iter::Extend">Extend</a><T> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></code><a href='#impl-Extend%3CT%3E' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#811-818' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.extend' class="method"><span id='extend.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/iter/trait.Extend.html#tymethod.extend' class='fnname'>extend</a><I: <a class="trait" href="../../../std/iter/trait.IntoIterator.html" title="trait std::iter::IntoIterator">IntoIterator</a><Item = T>>(&mut self, iter: I)</code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#815-817' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Extends a collection with the contents of an iterator. <a href="../../../std/iter/trait.Extend.html#tymethod.extend">Read more</a></p>
</div></div><h3 id='impl-Extend%3C%26%27a%20T%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<'a, T, S> <a class="trait" href="../../../std/iter/trait.Extend.html" title="trait std::iter::Extend">Extend</a><<a class="primitive" href="../../primitive.reference.html">&'a </a>T> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: 'a + <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/marker/trait.Copy.html" title="trait std::marker::Copy">Copy</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></code><a href='#impl-Extend%3C%26%27a%20T%3E' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.4.0'>1.4.0</div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#821-828' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.extend-1' class="method"><span id='extend.v-1' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/iter/trait.Extend.html#tymethod.extend' class='fnname'>extend</a><I: <a class="trait" href="../../../std/iter/trait.IntoIterator.html" title="trait std::iter::IntoIterator">IntoIterator</a><Item = <a class="primitive" href="../../primitive.reference.html">&'a </a>T>>(&mut self, iter: I)</code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#825-827' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Extends a collection with the contents of an iterator. <a href="../../../std/iter/trait.Extend.html#tymethod.extend">Read more</a></p>
</div></div><h3 id='impl-Default' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T, S> <a class="trait" href="../../../std/default/trait.Default.html" title="trait std::default::Default">Default</a> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a> + <a class="trait" href="../../../std/default/trait.Default.html" title="trait std::default::Default">Default</a>, </span></code><a href='#impl-Default' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#831-839' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='method.default' class="method"><span id='default.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/default/trait.Default.html#tymethod.default' class='fnname'>default</a>() -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#836-838' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Creates an empty <code>HashSet<T, S></code> with the <code>Default</code> value for the hasher.</p>
</div></div><h3 id='impl-BitOr%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<'a, 'b, T, S> <a class="trait" href="../../../std/ops/trait.BitOr.html" title="trait std::ops::BitOr">BitOr</a><&'b <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>> for &'a <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/clone/trait.Clone.html" title="trait std::clone::Clone">Clone</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a> + <a class="trait" href="../../../std/default/trait.Default.html" title="trait std::default::Default">Default</a>, </span></code><a href='#impl-BitOr%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#842-871' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='associatedtype.Output' class="type"><span id='Output.t' class='invisible'><code>type <a href='../../../std/ops/trait.BitOr.html#associatedtype.Output' class="type">Output</a> = <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></h4>
<div class='docblock'><p>The resulting type after applying the <code>|</code> operator.</p>
</div><h4 id='method.bitor' class="method"><span id='bitor.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/ops/trait.BitOr.html#tymethod.bitor' class='fnname'>bitor</a>(self, rhs: &<a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>) -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#868-870' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Returns the union of <code>self</code> and <code>rhs</code> as a new <code>HashSet<T, S></code>.</p>
<h1 id="examples-29" class="section-header"><a href="#examples-29">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"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">into_iter</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">b</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>].<span class="ident">into_iter</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">set</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">a</span> <span class="op">|</span> <span class="kw-2">&</span><span class="ident">b</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">i</span> <span class="op">=</span> <span class="number">0</span>;
<span class="kw">let</span> <span class="ident">expected</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="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="kw-2">&</span><span class="ident">set</span> {
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">expected</span>.<span class="ident">contains</span>(<span class="ident">x</span>));
<span class="ident">i</span> <span class="op">+=</span> <span class="number">1</span>;
}
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">i</span>, <span class="ident">expected</span>.<span class="ident">len</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20a%3A%20HashSet%3C_%3E%20%3D%20vec!%5B1%2C%202%2C%203%5D.into_iter().collect()%3B%0Alet%20b%3A%20HashSet%3C_%3E%20%3D%20vec!%5B3%2C%204%2C%205%5D.into_iter().collect()%3B%0A%0Alet%20set%20%3D%20%26a%20%7C%20%26b%3B%0A%0Alet%20mut%20i%20%3D%200%3B%0Alet%20expected%20%3D%20%5B1%2C%202%2C%203%2C%204%2C%205%5D%3B%0Afor%20x%20in%20%26set%20%7B%0A%20%20%20%20assert!(expected.contains(x))%3B%0A%20%20%20%20i%20%2B%3D%201%3B%0A%7D%0Aassert_eq!(i%2C%20expected.len())%3B%0A%7D">Run</a></pre>
</div></div><h3 id='impl-BitAnd%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<'a, 'b, T, S> <a class="trait" href="../../../std/ops/trait.BitAnd.html" title="trait std::ops::BitAnd">BitAnd</a><&'b <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>> for &'a <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/clone/trait.Clone.html" title="trait std::clone::Clone">Clone</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a> + <a class="trait" href="../../../std/default/trait.Default.html" title="trait std::default::Default">Default</a>, </span></code><a href='#impl-BitAnd%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#874-903' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='associatedtype.Output-1' class="type"><span id='Output.t-1' class='invisible'><code>type <a href='../../../std/ops/trait.BitAnd.html#associatedtype.Output' class="type">Output</a> = <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></h4>
<div class='docblock'><p>The resulting type after applying the <code>&</code> operator.</p>
</div><h4 id='method.bitand' class="method"><span id='bitand.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/ops/trait.BitAnd.html#tymethod.bitand' class='fnname'>bitand</a>(self, rhs: &<a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>) -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#900-902' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Returns the intersection of <code>self</code> and <code>rhs</code> as a new <code>HashSet<T, S></code>.</p>
<h1 id="examples-30" class="section-header"><a href="#examples-30">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"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">into_iter</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">b</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>].<span class="ident">into_iter</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">set</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">a</span> <span class="op">&</span> <span class="kw-2">&</span><span class="ident">b</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">i</span> <span class="op">=</span> <span class="number">0</span>;
<span class="kw">let</span> <span class="ident">expected</span> <span class="op">=</span> [<span class="number">2</span>, <span class="number">3</span>];
<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="kw-2">&</span><span class="ident">set</span> {
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">expected</span>.<span class="ident">contains</span>(<span class="ident">x</span>));
<span class="ident">i</span> <span class="op">+=</span> <span class="number">1</span>;
}
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">i</span>, <span class="ident">expected</span>.<span class="ident">len</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20a%3A%20HashSet%3C_%3E%20%3D%20vec!%5B1%2C%202%2C%203%5D.into_iter().collect()%3B%0Alet%20b%3A%20HashSet%3C_%3E%20%3D%20vec!%5B2%2C%203%2C%204%5D.into_iter().collect()%3B%0A%0Alet%20set%20%3D%20%26a%20%26%20%26b%3B%0A%0Alet%20mut%20i%20%3D%200%3B%0Alet%20expected%20%3D%20%5B2%2C%203%5D%3B%0Afor%20x%20in%20%26set%20%7B%0A%20%20%20%20assert!(expected.contains(x))%3B%0A%20%20%20%20i%20%2B%3D%201%3B%0A%7D%0Aassert_eq!(i%2C%20expected.len())%3B%0A%7D">Run</a></pre>
</div></div><h3 id='impl-BitXor%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<'a, 'b, T, S> <a class="trait" href="../../../std/ops/trait.BitXor.html" title="trait std::ops::BitXor">BitXor</a><&'b <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>> for &'a <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/clone/trait.Clone.html" title="trait std::clone::Clone">Clone</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a> + <a class="trait" href="../../../std/default/trait.Default.html" title="trait std::default::Default">Default</a>, </span></code><a href='#impl-BitXor%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#906-935' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='associatedtype.Output-2' class="type"><span id='Output.t-2' class='invisible'><code>type <a href='../../../std/ops/trait.BitXor.html#associatedtype.Output' class="type">Output</a> = <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></h4>
<div class='docblock'><p>The resulting type after applying the <code>^</code> operator.</p>
</div><h4 id='method.bitxor' class="method"><span id='bitxor.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/ops/trait.BitXor.html#tymethod.bitxor' class='fnname'>bitxor</a>(self, rhs: &<a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>) -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#932-934' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Returns the symmetric difference of <code>self</code> and <code>rhs</code> as a new <code>HashSet<T, S></code>.</p>
<h1 id="examples-31" class="section-header"><a href="#examples-31">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"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">into_iter</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">b</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>].<span class="ident">into_iter</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">set</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">a</span> <span class="op">^</span> <span class="kw-2">&</span><span class="ident">b</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">i</span> <span class="op">=</span> <span class="number">0</span>;
<span class="kw">let</span> <span class="ident">expected</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>, <span class="number">4</span>, <span class="number">5</span>];
<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="kw-2">&</span><span class="ident">set</span> {
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">expected</span>.<span class="ident">contains</span>(<span class="ident">x</span>));
<span class="ident">i</span> <span class="op">+=</span> <span class="number">1</span>;
}
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">i</span>, <span class="ident">expected</span>.<span class="ident">len</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20a%3A%20HashSet%3C_%3E%20%3D%20vec!%5B1%2C%202%2C%203%5D.into_iter().collect()%3B%0Alet%20b%3A%20HashSet%3C_%3E%20%3D%20vec!%5B3%2C%204%2C%205%5D.into_iter().collect()%3B%0A%0Alet%20set%20%3D%20%26a%20%5E%20%26b%3B%0A%0Alet%20mut%20i%20%3D%200%3B%0Alet%20expected%20%3D%20%5B1%2C%202%2C%204%2C%205%5D%3B%0Afor%20x%20in%20%26set%20%7B%0A%20%20%20%20assert!(expected.contains(x))%3B%0A%20%20%20%20i%20%2B%3D%201%3B%0A%7D%0Aassert_eq!(i%2C%20expected.len())%3B%0A%7D">Run</a></pre>
</div></div><h3 id='impl-Sub%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<'a, 'b, T, S> <a class="trait" href="../../../std/ops/trait.Sub.html" title="trait std::ops::Sub">Sub</a><&'b <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>> for &'a <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a> + <a class="trait" href="../../../std/clone/trait.Clone.html" title="trait std::clone::Clone">Clone</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a> + <a class="trait" href="../../../std/default/trait.Default.html" title="trait std::default::Default">Default</a>, </span></code><a href='#impl-Sub%3C%26%27b%20HashSet%3CT%2C%20S%3E%3E' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#938-967' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='associatedtype.Output-3' class="type"><span id='Output.t-3' class='invisible'><code>type <a href='../../../std/ops/trait.Sub.html#associatedtype.Output' class="type">Output</a> = <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></h4>
<div class='docblock'><p>The resulting type after applying the <code>-</code> operator.</p>
</div><h4 id='method.sub' class="method"><span id='sub.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/ops/trait.Sub.html#tymethod.sub' class='fnname'>sub</a>(self, rhs: &<a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S>) -> <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#964-966' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Returns the difference of <code>self</code> and <code>rhs</code> as a new <code>HashSet<T, S></code>.</p>
<h1 id="examples-32" class="section-header"><a href="#examples-32">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"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>].<span class="ident">into_iter</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">b</span>: <span class="ident">HashSet</span><span class="op"><</span><span class="kw">_</span><span class="op">></span> <span class="op">=</span> <span class="macro">vec</span><span class="macro">!</span>[<span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>].<span class="ident">into_iter</span>().<span class="ident">collect</span>();
<span class="kw">let</span> <span class="ident">set</span> <span class="op">=</span> <span class="kw-2">&</span><span class="ident">a</span> <span class="op">-</span> <span class="kw-2">&</span><span class="ident">b</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">i</span> <span class="op">=</span> <span class="number">0</span>;
<span class="kw">let</span> <span class="ident">expected</span> <span class="op">=</span> [<span class="number">1</span>, <span class="number">2</span>];
<span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="kw-2">&</span><span class="ident">set</span> {
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">expected</span>.<span class="ident">contains</span>(<span class="ident">x</span>));
<span class="ident">i</span> <span class="op">+=</span> <span class="number">1</span>;
}
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">i</span>, <span class="ident">expected</span>.<span class="ident">len</span>());<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0A%0Alet%20a%3A%20HashSet%3C_%3E%20%3D%20vec!%5B1%2C%202%2C%203%5D.into_iter().collect()%3B%0Alet%20b%3A%20HashSet%3C_%3E%20%3D%20vec!%5B3%2C%204%2C%205%5D.into_iter().collect()%3B%0A%0Alet%20set%20%3D%20%26a%20-%20%26b%3B%0A%0Alet%20mut%20i%20%3D%200%3B%0Alet%20expected%20%3D%20%5B1%2C%202%5D%3B%0Afor%20x%20in%20%26set%20%7B%0A%20%20%20%20assert!(expected.contains(x))%3B%0A%20%20%20%20i%20%2B%3D%201%3B%0A%7D%0Aassert_eq!(i%2C%20expected.len())%3B%0A%7D">Run</a></pre>
</div></div><h3 id='impl-IntoIterator' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<'a, T, S> <a class="trait" href="../../../std/iter/trait.IntoIterator.html" title="trait std::iter::IntoIterator">IntoIterator</a> for &'a <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></code><a href='#impl-IntoIterator' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#1060-1070' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='associatedtype.Item' class="type"><span id='Item.t' class='invisible'><code>type <a href='../../../std/iter/trait.IntoIterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="../../primitive.reference.html">&'a </a>T</code></span></h4>
<div class='docblock'><p>The type of the elements being iterated over.</p>
</div><h4 id='associatedtype.IntoIter' class="type"><span id='IntoIter.t' class='invisible'><code>type <a href='../../../std/iter/trait.IntoIterator.html#associatedtype.IntoIter' class="type">IntoIter</a> = <a class="struct" href="../../../std/collections/hash_set/struct.Iter.html" title="struct std::collections::hash_set::Iter">Iter</a><'a, T></code></span></h4>
<div class='docblock'><p>Which kind of iterator are we turning this into?</p>
</div><h4 id='method.into_iter' class="method"><div class="important-traits"><div class='tooltip'>ⓘ<span class='tooltiptext'>Important traits for <a class="struct" href="../../../std/collections/hash_set/struct.Iter.html" title="struct std::collections::hash_set::Iter">Iter</a><'a, K></span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="../../../std/collections/hash_set/struct.Iter.html" title="struct std::collections::hash_set::Iter">Iter</a><'a, K></h3><code class="content"><span class="where fmt-newline">impl<'a, K> <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a> for <a class="struct" href="../../../std/collections/hash_set/struct.Iter.html" title="struct std::collections::hash_set::Iter">Iter</a><'a, K></span><span class="where fmt-newline"> type <a href='../../../std/iter/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = <a class="primitive" href="../../primitive.reference.html">&'a </a>K;</span></code></div></div><span id='into_iter.v' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/iter/trait.IntoIterator.html#tymethod.into_iter' class='fnname'>into_iter</a>(self) -> <a class="struct" href="../../../std/collections/hash_set/struct.Iter.html" title="struct std::collections::hash_set::Iter">Iter</a><'a, T></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#1067-1069' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Creates an iterator from a value. <a href="../../../std/iter/trait.IntoIterator.html#tymethod.into_iter">Read more</a></p>
</div></div><h3 id='impl-IntoIterator-1' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T, S> <a class="trait" href="../../../std/iter/trait.IntoIterator.html" title="trait std::iter::IntoIterator">IntoIterator</a> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> T: <a class="trait" href="../../../std/cmp/trait.Eq.html" title="trait std::cmp::Eq">Eq</a> + <a class="trait" href="../../../std/hash/trait.Hash.html" title="trait std::hash::Hash">Hash</a>,<br> S: <a class="trait" href="../../../std/hash/trait.BuildHasher.html" title="trait std::hash::BuildHasher">BuildHasher</a>, </span></code><a href='#impl-IntoIterator-1' class='anchor'></a></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#1073-1103' title='goto source code'>[src]</a></span></td></tr></tbody></table></h3><div class='impl-items'><h4 id='associatedtype.Item-1' class="type"><span id='Item.t-1' class='invisible'><code>type <a href='../../../std/iter/trait.IntoIterator.html#associatedtype.Item' class="type">Item</a> = T</code></span></h4>
<div class='docblock'><p>The type of the elements being iterated over.</p>
</div><h4 id='associatedtype.IntoIter-1' class="type"><span id='IntoIter.t-1' class='invisible'><code>type <a href='../../../std/iter/trait.IntoIterator.html#associatedtype.IntoIter' class="type">IntoIter</a> = <a class="struct" href="../../../std/collections/hash_set/struct.IntoIter.html" title="struct std::collections::hash_set::IntoIter">IntoIter</a><T></code></span></h4>
<div class='docblock'><p>Which kind of iterator are we turning this into?</p>
</div><h4 id='method.into_iter-1' class="method"><div class="important-traits"><div class='tooltip'>ⓘ<span class='tooltiptext'>Important traits for <a class="struct" href="../../../std/collections/hash_set/struct.IntoIter.html" title="struct std::collections::hash_set::IntoIter">IntoIter</a><K></span></div><div class="content hidden"><h3 class="important">Important traits for <a class="struct" href="../../../std/collections/hash_set/struct.IntoIter.html" title="struct std::collections::hash_set::IntoIter">IntoIter</a><K></h3><code class="content"><span class="where fmt-newline">impl<K> <a class="trait" href="../../../std/iter/trait.Iterator.html" title="trait std::iter::Iterator">Iterator</a> for <a class="struct" href="../../../std/collections/hash_set/struct.IntoIter.html" title="struct std::collections::hash_set::IntoIter">IntoIter</a><K></span><span class="where fmt-newline"> type <a href='../../../std/iter/trait.Iterator.html#associatedtype.Item' class="type">Item</a> = K;</span></code></div></div><span id='into_iter.v-1' class='invisible'><table class='table-display'><tbody><tr><td><code>fn <a href='../../../std/iter/trait.IntoIterator.html#tymethod.into_iter' class='fnname'>into_iter</a>(self) -> <a class="struct" href="../../../std/collections/hash_set/struct.IntoIter.html" title="struct std::collections::hash_set::IntoIter">IntoIter</a><T></code></span></td><td><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../../src/std/collections/hash/set.rs.html#1100-1102' title='goto source code'>[src]</a></td></tr></tbody></table></span></h4><div class='docblock'><p>Creates a consuming iterator, that is, one that moves each value out
of the set in arbitrary order. The set cannot be used after calling
this.</p>
<h1 id="examples-33" class="section-header"><a href="#examples-33">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">"a"</span>.<span class="ident">to_string</span>());
<span class="ident">set</span>.<span class="ident">insert</span>(<span class="string">"b"</span>.<span class="ident">to_string</span>());
<span class="comment">// Not possible to collect to a Vec<String> with a regular `.iter()`.</span>
<span class="kw">let</span> <span class="ident">v</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">String</span><span class="op">></span> <span class="op">=</span> <span class="ident">set</span>.<span class="ident">into_iter</span>().<span class="ident">collect</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="kw-2">&</span><span class="ident">v</span> {
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{}"</span>, <span class="ident">x</span>);
}<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Ause%20std%3A%3Acollections%3A%3AHashSet%3B%0Alet%20mut%20set%20%3D%20HashSet%3A%3Anew()%3B%0Aset.insert(%22a%22.to_string())%3B%0Aset.insert(%22b%22.to_string())%3B%0A%0A%2F%2F%20Not%20possible%20to%20collect%20to%20a%20Vec%3CString%3E%20with%20a%20regular%20%60.iter()%60.%0Alet%20v%3A%20Vec%3CString%3E%20%3D%20set.into_iter().collect()%3B%0A%0A%2F%2F%20Will%20print%20in%20an%20arbitrary%20order.%0Afor%20x%20in%20%26v%20%7B%0A%20%20%20%20println!(%22%7B%7D%22%2C%20x)%3B%0A%7D%0A%7D">Run</a></pre>
</div></div></div>
<h2 id='synthetic-implementations' class='small-section-header'>
Auto Trait Implementations<a href='#synthetic-implementations' class='anchor'></a>
</h2>
<div id='synthetic-implementations-list'>
<h3 id='impl-Send' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T, S> <a class="trait" href="../../../std/marker/trait.Send.html" title="trait std::marker::Send">Send</a> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> S: <a class="trait" href="../../../std/marker/trait.Send.html" title="trait std::marker::Send">Send</a>,<br> T: <a class="trait" href="../../../std/marker/trait.Send.html" title="trait std::marker::Send">Send</a>, </span></code><a href='#impl-Send' class='anchor'></a></span></td><td><span class='out-of-band'></span></td></tr></tbody></table></h3><div class='impl-items'></div><h3 id='impl-Sync' class='impl'><span class='in-band'><table class='table-display'><tbody><tr><td><code>impl<T, S> <a class="trait" href="../../../std/marker/trait.Sync.html" title="trait std::marker::Sync">Sync</a> for <a class="struct" href="../../../std/collections/struct.HashSet.html" title="struct std::collections::HashSet">HashSet</a><T, S> <span class="where fmt-newline">where<br> S: <a class="trait" href="../../../std/marker/trait.Sync.html" title="trait std::marker::Sync">Sync</a>,<br> T: <a class="trait" href="../../../std/marker/trait.Sync.html" title="trait std::marker::Sync">Sync</a>, </span></code><a href='#impl-Sync' class='anchor'></a></span></td><td><span class='out-of-band'></span></td></tr></tbody></table></h3><div class='impl-items'></div></div></section><section id="search" class="content hidden"></section><section class="footer"></section><aside id="help" class="hidden"><div><h1 class="hidden">Help</h1><div class="shortcuts"><h2>Keyboard Shortcuts</h2><dl><dt><kbd>?</kbd></dt><dd>Show this help dialog</dd><dt><kbd>S</kbd></dt><dd>Focus the search field</dd><dt><kbd>↑</kbd></dt><dd>Move up in search results</dd><dt><kbd>↓</kbd></dt><dd>Move down in search results</dd><dt><kbd>↹</kbd></dt><dd>Switch tab</dd><dt><kbd>⏎</kbd></dt><dd>Go to active search result</dd><dt><kbd>+</kbd></dt><dd>Expand all sections</dd><dt><kbd>-</kbd></dt><dd>Collapse all sections</dd></dl></div><div class="infos"><h2>Search Tricks</h2><p>Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type.</p><p>Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>.</p><p>Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>)</p><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../../../";window.currentCrate = "std";</script><script src="../../../aliases.js"></script><script src="../../../main.js"></script><script defer src="../../../search-index.js"></script></body></html>
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