| <!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="`IndexMap` is a hash table where the iteration order of the key-value pairs is independent of the hash values of the keys."><meta name="keywords" content="rust, rustlang, rust-lang, indexmap"><title>indexmap - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../normalize.css"><link rel="stylesheet" href="../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../ayu.css" disabled><link rel="stylesheet" href="../dark.css" disabled><link rel="stylesheet" href="../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../storage.js"></script><script defer src="../crates.js"></script><script defer src="../main.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../favicon.svg"></head><body class="rustdoc mod crate"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">☰</button><a class="sidebar-logo" href="../indexmap/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../indexmap/index.html"><div class="logo-container"><img class="rust-logo" src="../rust-logo.svg" alt="logo"></div></a><h2 class="location"><a href="#">Crate indexmap</a></h2><div class="sidebar-elems"><ul class="block"><li class="version">Version 1.9.3</li><li><a id="all-types" href="all.html">All Items</a></li></ul><section><ul class="block"><li><a href="#reexports">Re-exports</a></li><li><a href="#modules">Modules</a></li><li><a href="#macros">Macros</a></li><li><a href="#traits">Traits</a></li></ul></section></div></nav><main><div class="width-limiter"><nav class="sub"><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="main-heading"><h1 class="fqn">Crate <a class="mod" href="#">indexmap</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../clipboard.svg" width="19" height="18" alt="Copy item path"></button></h1><span class="out-of-band"><a class="srclink" href="../src/indexmap/lib.rs.html#2-194">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p><a href="map/struct.IndexMap.html"><code>IndexMap</code></a> is a hash table where the iteration order of the key-value |
| pairs is independent of the hash values of the keys.</p> |
| <p><a href="set/struct.IndexSet.html"><code>IndexSet</code></a> is a corresponding hash set using the same implementation and |
| with similar properties.</p> |
| <h4 id="feature-highlights"><a href="#feature-highlights">Feature Highlights</a></h4> |
| <p><a href="map/struct.IndexMap.html"><code>IndexMap</code></a> and <a href="set/struct.IndexSet.html"><code>IndexSet</code></a> are drop-in compatible with the std <code>HashMap</code> |
| and <code>HashSet</code>, but they also have some features of note:</p> |
| <ul> |
| <li>The ordering semantics (see their documentation for details)</li> |
| <li>Sorting methods and the <a href="map/struct.IndexMap.html#method.pop" title="IndexMap::pop"><code>.pop()</code></a> methods.</li> |
| <li>The <a href="trait.Equivalent.html" title="Equivalent"><code>Equivalent</code></a> trait, which offers more flexible equality definitions |
| between borrowed and owned versions of keys.</li> |
| <li>The <a href="map/trait.MutableKeys.html" title="map::MutableKeys"><code>MutableKeys</code></a> trait, which gives opt-in mutable |
| access to hash map keys.</li> |
| </ul> |
| <h4 id="alternate-hashers"><a href="#alternate-hashers">Alternate Hashers</a></h4> |
| <p><a href="map/struct.IndexMap.html"><code>IndexMap</code></a> and <a href="set/struct.IndexSet.html"><code>IndexSet</code></a> have a default hasher type <code>S = RandomState</code>, |
| just like the standard <code>HashMap</code> and <code>HashSet</code>, which is resistant to |
| HashDoS attacks but not the most performant. Type aliases can make it easier |
| to use alternate hashers:</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>fnv::FnvBuildHasher; |
| <span class="kw">use </span>fxhash::FxBuildHasher; |
| <span class="kw">use </span>indexmap::{IndexMap, IndexSet}; |
| |
| <span class="kw">type </span>FnvIndexMap<K, V> = IndexMap<K, V, FnvBuildHasher>; |
| <span class="kw">type </span>FnvIndexSet<T> = IndexSet<T, FnvBuildHasher>; |
| |
| <span class="kw">type </span>FxIndexMap<K, V> = IndexMap<K, V, FxBuildHasher>; |
| <span class="kw">type </span>FxIndexSet<T> = IndexSet<T, FxBuildHasher>; |
| |
| <span class="kw">let </span>std: IndexSet<i32> = (<span class="number">0</span>..<span class="number">100</span>).collect(); |
| <span class="kw">let </span>fnv: FnvIndexSet<i32> = (<span class="number">0</span>..<span class="number">100</span>).collect(); |
| <span class="kw">let </span>fx: FxIndexSet<i32> = (<span class="number">0</span>..<span class="number">100</span>).collect(); |
| <span class="macro">assert_eq!</span>(std, fnv); |
| <span class="macro">assert_eq!</span>(std, fx);</code></pre></div> |
| <h4 id="rust-version"><a href="#rust-version">Rust Version</a></h4> |
| <p>This version of indexmap requires Rust 1.56 or later.</p> |
| <p>The indexmap 1.x release series will use a carefully considered version |
| upgrade policy, where in a later 1.x version, we will raise the minimum |
| required Rust version.</p> |
| <h3 id="no-standard-library-targets"><a href="#no-standard-library-targets">No Standard Library Targets</a></h3> |
| <p>This crate supports being built without <code>std</code>, requiring |
| <code>alloc</code> instead. This is enabled automatically when it is detected that |
| <code>std</code> is not available. There is no crate feature to enable/disable to |
| trigger this. It can be tested by building for a std-less target.</p> |
| <ul> |
| <li>Creating maps and sets using <a href="map/struct.IndexMap.html#method.new" title="IndexMap::new"><code>new</code></a> and |
| <a href="map/struct.IndexMap.html#method.with_capacity" title="IndexMap::with_capacity"><code>with_capacity</code></a> is unavailable without <code>std</code>.<br /> |
| Use methods <a href="map/struct.IndexMap.html#impl-Default"><code>IndexMap::default</code></a>, |
| <a href="map/struct.IndexMap.html#method.with_hasher" title="IndexMap::with_hasher"><code>with_hasher</code></a>, |
| <a href="map/struct.IndexMap.html#method.with_capacity_and_hasher" title="IndexMap::with_capacity_and_hasher"><code>with_capacity_and_hasher</code></a> instead. |
| A no-std compatible hasher will be needed as well, for example |
| from the crate <code>twox-hash</code>.</li> |
| <li>Macros <a href="macro.indexmap.html" title="indexmap!"><code>indexmap!</code></a> and <a href="macro.indexset.html" title="indexset!"><code>indexset!</code></a> are unavailable without <code>std</code>.</li> |
| </ul> |
| </div></details><h2 id="reexports" class="small-section-header"><a href="#reexports">Re-exports</a></h2><div class="item-table"><div class="item-row"><div class="item-left import-item" id="reexport.IndexMap"><code>pub use crate::map::<a class="struct" href="map/struct.IndexMap.html" title="struct indexmap::map::IndexMap">IndexMap</a>;</code></div></div><div class="item-row"><div class="item-left import-item" id="reexport.IndexSet"><code>pub use crate::set::<a class="struct" href="set/struct.IndexSet.html" title="struct indexmap::set::IndexSet">IndexSet</a>;</code></div></div></div><h2 id="modules" class="small-section-header"><a href="#modules">Modules</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="mod" href="map/index.html" title="indexmap::map mod">map</a></div><div class="item-right docblock-short"><code>IndexMap</code> is a hash table where the iteration order of the key-value |
| pairs is independent of the hash values of the keys.</div></div><div class="item-row"><div class="item-left module-item"><a class="mod" href="set/index.html" title="indexmap::set mod">set</a></div><div class="item-right docblock-short">A hash set implemented using <code>IndexMap</code></div></div></div><h2 id="macros" class="small-section-header"><a href="#macros">Macros</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="macro" href="macro.indexmap.html" title="indexmap::indexmap macro">indexmap</a></div><div class="item-right docblock-short">Create an <code>IndexMap</code> from a list of key-value pairs</div></div><div class="item-row"><div class="item-left module-item"><a class="macro" href="macro.indexset.html" title="indexmap::indexset macro">indexset</a></div><div class="item-right docblock-short">Create an <code>IndexSet</code> from a list of values</div></div></div><h2 id="traits" class="small-section-header"><a href="#traits">Traits</a></h2><div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.Equivalent.html" title="indexmap::Equivalent trait">Equivalent</a></div><div class="item-right docblock-short">Key equivalence trait.</div></div></div></section></div></main><div id="rustdoc-vars" data-root-path="../" data-current-crate="indexmap" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
