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<!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="A compiled regular expression for searching Unicode haystacks."><title>Regex in regex - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-46f98efaafac5295.ttf.woff2,FiraSans-Regular-018c141bf0843ffd.woff2,FiraSans-Medium-8f9a781e4970d388.woff2,SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2,SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../static.files/normalize-76eba96aa4d2e634.css"><link rel="stylesheet" href="../static.files/rustdoc-dd39b87e5fcfba68.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" 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class="sidebar-crate"><h2><a href="../regex/index.html">regex</a><span class="version">1.10.5</span></h2></div><h2 class="location"><a href="#">Regex</a></h2><div class="sidebar-elems"><section><h3><a href="#implementations">Methods</a></h3><ul class="block method"><li><a href="#method.as_str">as_str</a></li><li><a href="#method.capture_locations">capture_locations</a></li><li><a href="#method.capture_names">capture_names</a></li><li><a href="#method.captures">captures</a></li><li><a href="#method.captures_at">captures_at</a></li><li><a href="#method.captures_iter">captures_iter</a></li><li><a href="#method.captures_len">captures_len</a></li><li><a href="#method.captures_read">captures_read</a></li><li><a href="#method.captures_read_at">captures_read_at</a></li><li><a href="#method.find">find</a></li><li><a href="#method.find_at">find_at</a></li><li><a href="#method.find_iter">find_iter</a></li><li><a href="#method.is_match">is_match</a></li><li><a href="#method.is_match_at">is_match_at</a></li><li><a href="#method.new">new</a></li><li><a href="#method.replace">replace</a></li><li><a href="#method.replace_all">replace_all</a></li><li><a href="#method.replacen">replacen</a></li><li><a href="#method.shortest_match">shortest_match</a></li><li><a href="#method.shortest_match_at">shortest_match_at</a></li><li><a href="#method.split">split</a></li><li><a href="#method.splitn">splitn</a></li><li><a href="#method.static_captures_len">static_captures_len</a></li></ul><h3><a href="#trait-implementations">Trait Implementations</a></h3><ul class="block trait-implementation"><li><a href="#impl-Clone-for-Regex">Clone</a></li><li><a href="#impl-Debug-for-Regex">Debug</a></li><li><a href="#impl-Display-for-Regex">Display</a></li><li><a href="#impl-FromStr-for-Regex">FromStr</a></li><li><a href="#impl-TryFrom%3C%26str%3E-for-Regex">TryFrom&lt;&amp;str&gt;</a></li><li><a href="#impl-TryFrom%3CString%3E-for-Regex">TryFrom&lt;String&gt;</a></li></ul><h3><a href="#synthetic-implementations">Auto Trait Implementations</a></h3><ul class="block synthetic-implementation"><li><a href="#impl-Freeze-for-Regex">Freeze</a></li><li><a href="#impl-RefUnwindSafe-for-Regex">RefUnwindSafe</a></li><li><a href="#impl-Send-for-Regex">Send</a></li><li><a href="#impl-Sync-for-Regex">Sync</a></li><li><a href="#impl-Unpin-for-Regex">Unpin</a></li><li><a href="#impl-UnwindSafe-for-Regex">UnwindSafe</a></li></ul><h3><a href="#blanket-implementations">Blanket Implementations</a></h3><ul class="block blanket-implementation"><li><a href="#impl-Any-for-T">Any</a></li><li><a href="#impl-Borrow%3CT%3E-for-T">Borrow&lt;T&gt;</a></li><li><a href="#impl-BorrowMut%3CT%3E-for-T">BorrowMut&lt;T&gt;</a></li><li><a href="#impl-From%3CT%3E-for-T">From&lt;T&gt;</a></li><li><a href="#impl-Into%3CU%3E-for-T">Into&lt;U&gt;</a></li><li><a href="#impl-ToOwned-for-T">ToOwned</a></li><li><a href="#impl-ToString-for-T">ToString</a></li><li><a href="#impl-TryFrom%3CU%3E-for-T">TryFrom&lt;U&gt;</a></li><li><a href="#impl-TryInto%3CU%3E-for-T">TryInto&lt;U&gt;</a></li></ul></section><h2><a href="index.html">In crate regex</a></h2></div></nav><div class="sidebar-resizer"></div><main><div class="width-limiter"><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><h1>Struct <a href="index.html">regex</a>::<wbr><a class="struct" href="#">Regex</a><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><span class="out-of-band"><a class="src" href="../src/regex/regex/string.rs.html#101-104">source</a> · <button id="toggle-all-docs" title="collapse all docs">[<span>&#x2212;</span>]</button></span></div><pre class="rust item-decl"><code>pub struct Regex { <span class="comment">/* private fields */</span> }</code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>A compiled regular expression for searching Unicode haystacks.</p>
<p>A <code>Regex</code> can be used to search haystacks, split haystacks into substrings
or replace substrings in a haystack with a different substring. All
searching is done with an implicit <code>(?s:.)*?</code> at the beginning and end of
an pattern. To force an expression to match the whole string (or a prefix
or a suffix), you must use an anchor like <code>^</code> or <code>$</code> (or <code>\A</code> and <code>\z</code>).</p>
<p>While this crate will handle Unicode strings (whether in the regular
expression or in the haystack), all positions returned are <strong>byte
offsets</strong>. Every byte offset is guaranteed to be at a Unicode code point
boundary. That is, all offsets returned by the <code>Regex</code> API are guaranteed
to be ranges that can slice a <code>&amp;str</code> without panicking. If you want to
relax this requirement, then you must search <code>&amp;[u8]</code> haystacks with a
<a href="bytes/struct.Regex.html" title="struct regex::bytes::Regex"><code>bytes::Regex</code></a>.</p>
<p>The only methods that allocate new strings are the string replacement
methods. All other methods (searching and splitting) return borrowed
references into the haystack given.</p>
<h2 id="example"><a class="doc-anchor" href="#example">§</a>Example</h2>
<p>Find the offsets of a US phone number:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">"[0-9]{3}-[0-9]{3}-[0-9]{4}"</span>).unwrap();
<span class="kw">let </span>m = re.find(<span class="string">"phone: 111-222-3333"</span>).unwrap();
<span class="macro">assert_eq!</span>(<span class="number">7</span>..<span class="number">19</span>, m.range());</code></pre></div>
<h2 id="example-extracting-capture-groups"><a class="doc-anchor" href="#example-extracting-capture-groups">§</a>Example: extracting capture groups</h2>
<p>A common way to use regexes is with capture groups. That is, instead of
just looking for matches of an entire regex, parentheses are used to create
groups that represent part of the match.</p>
<p>For example, consider a haystack with multiple lines, and each line has
three whitespace delimited fields where the second field is expected to be
a number and the third field a boolean. To make this convenient, we use
the <a href="struct.Captures.html#method.extract" title="method regex::Captures::extract"><code>Captures::extract</code></a> API to put the strings that match each group
into a fixed size array:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>hay = <span class="string">"
rabbit 54 true
groundhog 2 true
does not match
fox 109 false
"</span>;
<span class="kw">let </span>re = Regex::new(<span class="string">r"(?m)^\s*(\S+)\s+([0-9]+)\s+(true|false)\s*$"</span>).unwrap();
<span class="kw">let </span><span class="kw-2">mut </span>fields: Vec&lt;(<span class="kw-2">&amp;</span>str, i64, bool)&gt; = <span class="macro">vec!</span>[];
<span class="kw">for </span>(<span class="kw">_</span>, [f1, f2, f3]) <span class="kw">in </span>re.captures_iter(hay).map(|caps| caps.extract()) {
fields.push((f1, f2.parse()<span class="question-mark">?</span>, f3.parse()<span class="question-mark">?</span>));
}
<span class="macro">assert_eq!</span>(fields, <span class="macro">vec!</span>[
(<span class="string">"rabbit"</span>, <span class="number">54</span>, <span class="bool-val">true</span>),
(<span class="string">"groundhog"</span>, <span class="number">2</span>, <span class="bool-val">true</span>),
(<span class="string">"fox"</span>, <span class="number">109</span>, <span class="bool-val">false</span>),
]);
</code></pre></div>
<h2 id="example-searching-with-the-pattern-trait"><a class="doc-anchor" href="#example-searching-with-the-pattern-trait">§</a>Example: searching with the <code>Pattern</code> trait</h2>
<p><strong>Note</strong>: This section requires that this crate is compiled with the
<code>pattern</code> Cargo feature enabled, which <strong>requires nightly Rust</strong>.</p>
<p>Since <code>Regex</code> implements <code>Pattern</code> from the standard library, one can
use regexes with methods defined on <code>&amp;str</code>. For example, <code>is_match</code>,
<code>find</code>, <code>find_iter</code> and <code>split</code> can, in some cases, be replaced with
<code>str::contains</code>, <code>str::find</code>, <code>str::match_indices</code> and <code>str::split</code>.</p>
<p>Here are some examples:</p>
<div class="example-wrap ignore"><a href="#" class="tooltip" title="This example is not tested"></a><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"\d+"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"a111b222c"</span>;
<span class="macro">assert!</span>(hay.contains(<span class="kw-2">&amp;</span>re));
<span class="macro">assert_eq!</span>(hay.find(<span class="kw-2">&amp;</span>re), <span class="prelude-val">Some</span>(<span class="number">1</span>));
<span class="macro">assert_eq!</span>(hay.match_indices(<span class="kw-2">&amp;</span>re).collect::&lt;Vec&lt;<span class="kw">_</span>&gt;&gt;(), <span class="macro">vec!</span>[
(<span class="number">1</span>, <span class="string">"111"</span>),
(<span class="number">5</span>, <span class="string">"222"</span>),
]);
<span class="macro">assert_eq!</span>(hay.split(<span class="kw-2">&amp;</span>re).collect::&lt;Vec&lt;<span class="kw">_</span>&gt;&gt;(), <span class="macro">vec!</span>[<span class="string">"a"</span>, <span class="string">"b"</span>, <span class="string">"c"</span>]);</code></pre></div>
</div></details><h2 id="implementations" class="section-header">Implementations<a href="#implementations" class="anchor">§</a></h2><div id="implementations-list"><details class="toggle implementors-toggle" open><summary><section id="impl-Regex" class="impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#148-962">source</a><a href="#impl-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section></summary><div class="docblock"><p>Core regular expression methods.</p>
</div><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.new" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#180-182">source</a><h4 class="code-header">pub fn <a href="#method.new" class="fn">new</a>(re: &amp;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a>, <a class="enum" href="enum.Error.html" title="enum regex::Error">Error</a>&gt;</h4></section></summary><div class="docblock"><p>Compiles a regular expression. Once compiled, it can be used repeatedly
to search, split or replace substrings in a haystack.</p>
<p>Note that regex compilation tends to be a somewhat expensive process,
and unlike higher level environments, compilation is not automatically
cached for you. One should endeavor to compile a regex once and then
reuse it. For example, its a bad idea to compile the same regex
repeatedly in a loop.</p>
<h5 id="errors"><a class="doc-anchor" href="#errors">§</a>Errors</h5>
<p>If an invalid pattern is given, then an error is returned.
An error is also returned if the pattern is valid, but would
produce a regex that is bigger than the configured size limit via
<a href="struct.RegexBuilder.html#method.size_limit" title="method regex::RegexBuilder::size_limit"><code>RegexBuilder::size_limit</code></a>. (A reasonable size limit is enabled by
default.)</p>
<h5 id="example-1"><a class="doc-anchor" href="#example-1">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="comment">// An Invalid pattern because of an unclosed parenthesis
</span><span class="macro">assert!</span>(Regex::new(<span class="string">r"foo(bar"</span>).is_err());
<span class="comment">// An invalid pattern because the regex would be too big
// because Unicode tends to inflate things.
</span><span class="macro">assert!</span>(Regex::new(<span class="string">r"\w{1000}"</span>).is_err());
<span class="comment">// Disabling Unicode can make the regex much smaller,
// potentially by up to or more than an order of magnitude.
</span><span class="macro">assert!</span>(Regex::new(<span class="string">r"(?-u:\w){1000}"</span>).is_ok());</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.is_match" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#204-206">source</a><h4 class="code-header">pub fn <a href="#method.is_match" class="fn">is_match</a>(&amp;self, haystack: &amp;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.bool.html">bool</a></h4></section></summary><div class="docblock"><p>Returns true if and only if there is a match for the regex anywhere
in the haystack given.</p>
<p>It is recommended to use this method if all you need to do is test
whether a match exists, since the underlying matching engine may be
able to do less work.</p>
<h5 id="example-2"><a class="doc-anchor" href="#example-2">§</a>Example</h5>
<p>Test if some haystack contains at least one word with exactly 13
Unicode word characters:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"\b\w{13}\b"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"I categorically deny having triskaidekaphobia."</span>;
<span class="macro">assert!</span>(re.is_match(hay));</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.find" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#232-234">source</a><h4 class="code-header">pub fn <a href="#method.find" class="fn">find</a>&lt;'h&gt;(&amp;self, haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="struct.Match.html" title="struct regex::Match">Match</a>&lt;'h&gt;&gt;</h4></section></summary><div class="docblock"><p>This routine searches for the first match of this regex in the
haystack given, and if found, returns a <a href="struct.Match.html" title="struct regex::Match"><code>Match</code></a>. The <code>Match</code>
provides access to both the byte offsets of the match and the actual
substring that matched.</p>
<p>Note that this should only be used if you want to find the entire
match. If instead you just want to test the existence of a match,
its potentially faster to use <code>Regex::is_match(hay)</code> instead of
<code>Regex::find(hay).is_some()</code>.</p>
<h5 id="example-3"><a class="doc-anchor" href="#example-3">§</a>Example</h5>
<p>Find the first word with exactly 13 Unicode word characters:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"\b\w{13}\b"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"I categorically deny having triskaidekaphobia."</span>;
<span class="kw">let </span>mat = re.find(hay).unwrap();
<span class="macro">assert_eq!</span>(<span class="number">2</span>..<span class="number">15</span>, mat.range());
<span class="macro">assert_eq!</span>(<span class="string">"categorically"</span>, mat.as_str());</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.find_iter" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#264-266">source</a><h4 class="code-header">pub fn <a href="#method.find_iter" class="fn">find_iter</a>&lt;'r, 'h&gt;(&amp;'r self, haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>) -&gt; <a class="struct" href="struct.Matches.html" title="struct regex::Matches">Matches</a>&lt;'r, 'h&gt; <a href="#" class="tooltip" data-notable-ty="Matches&lt;&#39;r, &#39;h&gt;"></a></h4></section></summary><div class="docblock"><p>Returns an iterator that yields successive non-overlapping matches in
the given haystack. The iterator yields values of type <a href="struct.Match.html" title="struct regex::Match"><code>Match</code></a>.</p>
<h5 id="time-complexity"><a class="doc-anchor" href="#time-complexity">§</a>Time complexity</h5>
<p>Note that since <code>find_iter</code> runs potentially many searches on the
haystack and since each search has worst case <code>O(m * n)</code> time
complexity, the overall worst case time complexity for iteration is
<code>O(m * n^2)</code>.</p>
<h5 id="example-4"><a class="doc-anchor" href="#example-4">§</a>Example</h5>
<p>Find every word with exactly 13 Unicode word characters:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"\b\w{13}\b"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"Retroactively relinquishing remunerations is reprehensible."</span>;
<span class="kw">let </span>matches: Vec&lt;<span class="kw">_</span>&gt; = re.find_iter(hay).map(|m| m.as_str()).collect();
<span class="macro">assert_eq!</span>(matches, <span class="macro">vec!</span>[
<span class="string">"Retroactively"</span>,
<span class="string">"relinquishing"</span>,
<span class="string">"remunerations"</span>,
<span class="string">"reprehensible"</span>,
]);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.captures" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#355-357">source</a><h4 class="code-header">pub fn <a href="#method.captures" class="fn">captures</a>&lt;'h&gt;(&amp;self, haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="struct.Captures.html" title="struct regex::Captures">Captures</a>&lt;'h&gt;&gt;</h4></section></summary><div class="docblock"><p>This routine searches for the first match of this regex in the haystack
given, and if found, returns not only the overall match but also the
matches of each capture group in the regex. If no match is found, then
<code>None</code> is returned.</p>
<p>Capture group <code>0</code> always corresponds to an implicit unnamed group that
includes the entire match. If a match is found, this group is always
present. Subsequent groups may be named and are numbered, starting
at 1, by the order in which the opening parenthesis appears in the
pattern. For example, in the pattern <code>(?&lt;a&gt;.(?&lt;b&gt;.))(?&lt;c&gt;.)</code>, <code>a</code>,
<code>b</code> and <code>c</code> correspond to capture group indices <code>1</code>, <code>2</code> and <code>3</code>,
respectively.</p>
<p>You should only use <code>captures</code> if you need access to the capture group
matches. Otherwise, <a href="struct.Regex.html#method.find" title="method regex::Regex::find"><code>Regex::find</code></a> is generally faster for discovering
just the overall match.</p>
<h5 id="example-5"><a class="doc-anchor" href="#example-5">§</a>Example</h5>
<p>Say you have some haystack with movie names and their release years,
like “Citizen Kane (1941)”. Itd be nice if we could search for
substrings looking like that, while also extracting the movie name and
its release year separately. The example below shows how to do that.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"'([^']+)'\s+\((\d{4})\)"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"Not my favorite movie: 'Citizen Kane' (1941)."</span>;
<span class="kw">let </span>caps = re.captures(hay).unwrap();
<span class="macro">assert_eq!</span>(caps.get(<span class="number">0</span>).unwrap().as_str(), <span class="string">"'Citizen Kane' (1941)"</span>);
<span class="macro">assert_eq!</span>(caps.get(<span class="number">1</span>).unwrap().as_str(), <span class="string">"Citizen Kane"</span>);
<span class="macro">assert_eq!</span>(caps.get(<span class="number">2</span>).unwrap().as_str(), <span class="string">"1941"</span>);
<span class="comment">// You can also access the groups by index using the Index notation.
// Note that this will panic on an invalid index. In this case, these
// accesses are always correct because the overall regex will only
// match when these capture groups match.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="number">0</span>], <span class="string">"'Citizen Kane' (1941)"</span>);
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="number">1</span>], <span class="string">"Citizen Kane"</span>);
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="number">2</span>], <span class="string">"1941"</span>);</code></pre></div>
<p>Note that the full match is at capture group <code>0</code>. Each subsequent
capture group is indexed by the order of its opening <code>(</code>.</p>
<p>We can make this example a bit clearer by using <em>named</em> capture groups:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"'(?&lt;title&gt;[^']+)'\s+\((?&lt;year&gt;\d{4})\)"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"Not my favorite movie: 'Citizen Kane' (1941)."</span>;
<span class="kw">let </span>caps = re.captures(hay).unwrap();
<span class="macro">assert_eq!</span>(caps.get(<span class="number">0</span>).unwrap().as_str(), <span class="string">"'Citizen Kane' (1941)"</span>);
<span class="macro">assert_eq!</span>(caps.name(<span class="string">"title"</span>).unwrap().as_str(), <span class="string">"Citizen Kane"</span>);
<span class="macro">assert_eq!</span>(caps.name(<span class="string">"year"</span>).unwrap().as_str(), <span class="string">"1941"</span>);
<span class="comment">// You can also access the groups by name using the Index notation.
// Note that this will panic on an invalid group name. In this case,
// these accesses are always correct because the overall regex will
// only match when these capture groups match.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="number">0</span>], <span class="string">"'Citizen Kane' (1941)"</span>);
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="string">"title"</span>], <span class="string">"Citizen Kane"</span>);
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="string">"year"</span>], <span class="string">"1941"</span>);</code></pre></div>
<p>Here we name the capture groups, which we can access with the <code>name</code>
method or the <code>Index</code> notation with a <code>&amp;str</code>. Note that the named
capture groups are still accessible with <code>get</code> or the <code>Index</code> notation
with a <code>usize</code>.</p>
<p>The <code>0</code>th capture group is always unnamed, so it must always be
accessed with <code>get(0)</code> or <code>[0]</code>.</p>
<p>Finally, one other way to to get the matched substrings is with the
<a href="struct.Captures.html#method.extract" title="method regex::Captures::extract"><code>Captures::extract</code></a> API:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"'([^']+)'\s+\((\d{4})\)"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"Not my favorite movie: 'Citizen Kane' (1941)."</span>;
<span class="kw">let </span>(full, [title, year]) = re.captures(hay).unwrap().extract();
<span class="macro">assert_eq!</span>(full, <span class="string">"'Citizen Kane' (1941)"</span>);
<span class="macro">assert_eq!</span>(title, <span class="string">"Citizen Kane"</span>);
<span class="macro">assert_eq!</span>(year, <span class="string">"1941"</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.captures_iter" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#420-425">source</a><h4 class="code-header">pub fn <a href="#method.captures_iter" class="fn">captures_iter</a>&lt;'r, 'h&gt;(
&amp;'r self,
haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>,
) -&gt; <a class="struct" href="struct.CaptureMatches.html" title="struct regex::CaptureMatches">CaptureMatches</a>&lt;'r, 'h&gt; <a href="#" class="tooltip" data-notable-ty="CaptureMatches&lt;&#39;r, &#39;h&gt;"></a></h4></section></summary><div class="docblock"><p>Returns an iterator that yields successive non-overlapping matches in
the given haystack. The iterator yields values of type <a href="struct.Captures.html" title="struct regex::Captures"><code>Captures</code></a>.</p>
<p>This is the same as <a href="struct.Regex.html#method.find_iter" title="method regex::Regex::find_iter"><code>Regex::find_iter</code></a>, but instead of only providing
access to the overall match, each value yield includes access to the
matches of all capture groups in the regex. Reporting this extra match
data is potentially costly, so callers should only use <code>captures_iter</code>
over <code>find_iter</code> when they actually need access to the capture group
matches.</p>
<h5 id="time-complexity-1"><a class="doc-anchor" href="#time-complexity-1">§</a>Time complexity</h5>
<p>Note that since <code>captures_iter</code> runs potentially many searches on the
haystack and since each search has worst case <code>O(m * n)</code> time
complexity, the overall worst case time complexity for iteration is
<code>O(m * n^2)</code>.</p>
<h5 id="example-6"><a class="doc-anchor" href="#example-6">§</a>Example</h5>
<p>We can use this to find all movie titles and their release years in
some haystack, where the movie is formatted like “Title (xxxx)”:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"'([^']+)'\s+\(([0-9]{4})\)"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"'Citizen Kane' (1941), 'The Wizard of Oz' (1939), 'M' (1931)."</span>;
<span class="kw">let </span><span class="kw-2">mut </span>movies = <span class="macro">vec!</span>[];
<span class="kw">for </span>(<span class="kw">_</span>, [title, year]) <span class="kw">in </span>re.captures_iter(hay).map(|c| c.extract()) {
movies.push((title, year.parse::&lt;i64&gt;()<span class="question-mark">?</span>));
}
<span class="macro">assert_eq!</span>(movies, <span class="macro">vec!</span>[
(<span class="string">"Citizen Kane"</span>, <span class="number">1941</span>),
(<span class="string">"The Wizard of Oz"</span>, <span class="number">1939</span>),
(<span class="string">"M"</span>, <span class="number">1931</span>),
]);</code></pre></div>
<p>Or with named groups:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"'(?&lt;title&gt;[^']+)'\s+\((?&lt;year&gt;[0-9]{4})\)"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"'Citizen Kane' (1941), 'The Wizard of Oz' (1939), 'M' (1931)."</span>;
<span class="kw">let </span><span class="kw-2">mut </span>it = re.captures_iter(hay);
<span class="kw">let </span>caps = it.next().unwrap();
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="string">"title"</span>], <span class="string">"Citizen Kane"</span>);
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="string">"year"</span>], <span class="string">"1941"</span>);
<span class="kw">let </span>caps = it.next().unwrap();
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="string">"title"</span>], <span class="string">"The Wizard of Oz"</span>);
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="string">"year"</span>], <span class="string">"1939"</span>);
<span class="kw">let </span>caps = it.next().unwrap();
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="string">"title"</span>], <span class="string">"M"</span>);
<span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>caps[<span class="string">"year"</span>], <span class="string">"1931"</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.split" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#553-555">source</a><h4 class="code-header">pub fn <a href="#method.split" class="fn">split</a>&lt;'r, 'h&gt;(&amp;'r self, haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>) -&gt; <a class="struct" href="struct.Split.html" title="struct regex::Split">Split</a>&lt;'r, 'h&gt; <a href="#" class="tooltip" data-notable-ty="Split&lt;&#39;r, &#39;h&gt;"></a></h4></section></summary><div class="docblock"><p>Returns an iterator of substrings of the haystack given, delimited by a
match of the regex. Namely, each element of the iterator corresponds to
a part of the haystack that <em>isnt</em> matched by the regular expression.</p>
<h5 id="time-complexity-2"><a class="doc-anchor" href="#time-complexity-2">§</a>Time complexity</h5>
<p>Since iterators over all matches requires running potentially many
searches on the haystack, and since each search has worst case
<code>O(m * n)</code> time complexity, the overall worst case time complexity for
this routine is <code>O(m * n^2)</code>.</p>
<h5 id="example-7"><a class="doc-anchor" href="#example-7">§</a>Example</h5>
<p>To split a string delimited by arbitrary amounts of spaces or tabs:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"[ \t]+"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"a b \t c\td e"</span>;
<span class="kw">let </span>fields: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(fields, <span class="macro">vec!</span>[<span class="string">"a"</span>, <span class="string">"b"</span>, <span class="string">"c"</span>, <span class="string">"d"</span>, <span class="string">"e"</span>]);</code></pre></div>
<h5 id="example-more-cases"><a class="doc-anchor" href="#example-more-cases">§</a>Example: more cases</h5>
<p>Basic usage:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r" "</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"Mary had a little lamb"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">"Mary"</span>, <span class="string">"had"</span>, <span class="string">"a"</span>, <span class="string">"little"</span>, <span class="string">"lamb"</span>]);
<span class="kw">let </span>re = Regex::new(<span class="string">r"X"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">""</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">""</span>]);
<span class="kw">let </span>re = Regex::new(<span class="string">r"X"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"lionXXtigerXleopard"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">"lion"</span>, <span class="string">""</span>, <span class="string">"tiger"</span>, <span class="string">"leopard"</span>]);
<span class="kw">let </span>re = Regex::new(<span class="string">r"::"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"lion::tiger::leopard"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">"lion"</span>, <span class="string">"tiger"</span>, <span class="string">"leopard"</span>]);</code></pre></div>
<p>If a haystack contains multiple contiguous matches, you will end up
with empty spans yielded by the iterator:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"X"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"XXXXaXXbXc"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">""</span>, <span class="string">""</span>, <span class="string">""</span>, <span class="string">""</span>, <span class="string">"a"</span>, <span class="string">""</span>, <span class="string">"b"</span>, <span class="string">"c"</span>]);
<span class="kw">let </span>re = Regex::new(<span class="string">r"/"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"(///)"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">"("</span>, <span class="string">""</span>, <span class="string">""</span>, <span class="string">")"</span>]);</code></pre></div>
<p>Separators at the start or end of a haystack are neighbored by empty
substring.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"0"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"010"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">""</span>, <span class="string">"1"</span>, <span class="string">""</span>]);</code></pre></div>
<p>When the empty string is used as a regex, it splits at every valid
UTF-8 boundary by default (which includes the beginning and end of the
haystack):</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r""</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"rust"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">""</span>, <span class="string">"r"</span>, <span class="string">"u"</span>, <span class="string">"s"</span>, <span class="string">"t"</span>, <span class="string">""</span>]);
<span class="comment">// Splitting by an empty string is UTF-8 aware by default!
</span><span class="kw">let </span>re = Regex::new(<span class="string">r""</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"☃"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">""</span>, <span class="string">"☃"</span>, <span class="string">""</span>]);</code></pre></div>
<p>Contiguous separators (commonly shows up with whitespace), can lead to
possibly surprising behavior. For example, this code is correct:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r" "</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">" a b c"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">""</span>, <span class="string">""</span>, <span class="string">""</span>, <span class="string">""</span>, <span class="string">"a"</span>, <span class="string">""</span>, <span class="string">"b"</span>, <span class="string">"c"</span>]);</code></pre></div>
<p>It does <em>not</em> give you <code>[&quot;a&quot;, &quot;b&quot;, &quot;c&quot;]</code>. For that behavior, youd want
to match contiguous space characters:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r" +"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">" a b c"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.split(hay).collect();
<span class="comment">// N.B. This does still include a leading empty span because ' +'
// matches at the beginning of the haystack.
</span><span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">""</span>, <span class="string">"a"</span>, <span class="string">"b"</span>, <span class="string">"c"</span>]);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.splitn" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#628-634">source</a><h4 class="code-header">pub fn <a href="#method.splitn" class="fn">splitn</a>&lt;'r, 'h&gt;(
&amp;'r self,
haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>,
limit: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>,
) -&gt; <a class="struct" href="struct.SplitN.html" title="struct regex::SplitN">SplitN</a>&lt;'r, 'h&gt; <a href="#" class="tooltip" data-notable-ty="SplitN&lt;&#39;r, &#39;h&gt;"></a></h4></section></summary><div class="docblock"><p>Returns an iterator of at most <code>limit</code> substrings of the haystack
given, delimited by a match of the regex. (A <code>limit</code> of <code>0</code> will return
no substrings.) Namely, each element of the iterator corresponds to a
part of the haystack that <em>isnt</em> matched by the regular expression.
The remainder of the haystack that is not split will be the last
element in the iterator.</p>
<h5 id="time-complexity-3"><a class="doc-anchor" href="#time-complexity-3">§</a>Time complexity</h5>
<p>Since iterators over all matches requires running potentially many
searches on the haystack, and since each search has worst case
<code>O(m * n)</code> time complexity, the overall worst case time complexity for
this routine is <code>O(m * n^2)</code>.</p>
<p>Although note that the worst case time here has an upper bound given
by the <code>limit</code> parameter.</p>
<h5 id="example-8"><a class="doc-anchor" href="#example-8">§</a>Example</h5>
<p>Get the first two words in some haystack:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"\W+"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"Hey! How are you?"</span>;
<span class="kw">let </span>fields: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.splitn(hay, <span class="number">3</span>).collect();
<span class="macro">assert_eq!</span>(fields, <span class="macro">vec!</span>[<span class="string">"Hey"</span>, <span class="string">"How"</span>, <span class="string">"are you?"</span>]);</code></pre></div>
<h5 id="examples-more-cases"><a class="doc-anchor" href="#examples-more-cases">§</a>Examples: more cases</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r" "</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"Mary had a little lamb"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.splitn(hay, <span class="number">3</span>).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">"Mary"</span>, <span class="string">"had"</span>, <span class="string">"a little lamb"</span>]);
<span class="kw">let </span>re = Regex::new(<span class="string">r"X"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">""</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.splitn(hay, <span class="number">3</span>).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">""</span>]);
<span class="kw">let </span>re = Regex::new(<span class="string">r"X"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"lionXXtigerXleopard"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.splitn(hay, <span class="number">3</span>).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">"lion"</span>, <span class="string">""</span>, <span class="string">"tigerXleopard"</span>]);
<span class="kw">let </span>re = Regex::new(<span class="string">r"::"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"lion::tiger::leopard"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.splitn(hay, <span class="number">2</span>).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">"lion"</span>, <span class="string">"tiger::leopard"</span>]);
<span class="kw">let </span>re = Regex::new(<span class="string">r"X"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"abcXdef"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.splitn(hay, <span class="number">1</span>).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">"abcXdef"</span>]);
<span class="kw">let </span>re = Regex::new(<span class="string">r"X"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"abcdef"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.splitn(hay, <span class="number">2</span>).collect();
<span class="macro">assert_eq!</span>(got, <span class="macro">vec!</span>[<span class="string">"abcdef"</span>]);
<span class="kw">let </span>re = Regex::new(<span class="string">r"X"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"abcXdef"</span>;
<span class="kw">let </span>got: Vec&lt;<span class="kw-2">&amp;</span>str&gt; = re.splitn(hay, <span class="number">0</span>).collect();
<span class="macro">assert!</span>(got.is_empty());</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.replace" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#742-748">source</a><h4 class="code-header">pub fn <a href="#method.replace" class="fn">replace</a>&lt;'h, R: <a class="trait" href="trait.Replacer.html" title="trait regex::Replacer">Replacer</a>&gt;(
&amp;self,
haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>,
rep: R,
) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/alloc/borrow/enum.Cow.html" title="enum alloc::borrow::Cow">Cow</a>&lt;'h, <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>&gt;</h4></section></summary><div class="docblock"><p>Replaces the leftmost-first match in the given haystack with the
replacement provided. The replacement can be a regular string (where
<code>$N</code> and <code>$name</code> are expanded to match capture groups) or a function
that takes a <a href="struct.Captures.html" title="struct regex::Captures"><code>Captures</code></a> and returns the replaced string.</p>
<p>If no match is found, then the haystack is returned unchanged. In that
case, this implementation will likely return a <code>Cow::Borrowed</code> value
such that no allocation is performed.</p>
<p>When a <code>Cow::Borrowed</code> is returned, the value returned is guaranteed
to be equivalent to the <code>haystack</code> given.</p>
<h5 id="replacement-string-syntax"><a class="doc-anchor" href="#replacement-string-syntax">§</a>Replacement string syntax</h5>
<p>All instances of <code>$ref</code> in the replacement string are replaced with
the substring corresponding to the capture group identified by <code>ref</code>.</p>
<p><code>ref</code> may be an integer corresponding to the index of the capture group
(counted by order of opening parenthesis where <code>0</code> is the entire match)
or it can be a name (consisting of letters, digits or underscores)
corresponding to a named capture group.</p>
<p>If <code>ref</code> isnt a valid capture group (whether the name doesnt exist or
isnt a valid index), then it is replaced with the empty string.</p>
<p>The longest possible name is used. For example, <code>$1a</code> looks up the
capture group named <code>1a</code> and not the capture group at index <code>1</code>. To
exert more precise control over the name, use braces, e.g., <code>${1}a</code>.</p>
<p>To write a literal <code>$</code> use <code>$$</code>.</p>
<h5 id="example-9"><a class="doc-anchor" href="#example-9">§</a>Example</h5>
<p>Note that this function is polymorphic with respect to the replacement.
In typical usage, this can just be a normal string:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"[^01]+"</span>).unwrap();
<span class="macro">assert_eq!</span>(re.replace(<span class="string">"1078910"</span>, <span class="string">""</span>), <span class="string">"1010"</span>);</code></pre></div>
<p>But anything satisfying the <a href="trait.Replacer.html" title="trait regex::Replacer"><code>Replacer</code></a> trait will work. For example,
a closure of type <code>|&amp;Captures| -&gt; String</code> provides direct access to the
captures corresponding to a match. This allows one to access capturing
group matches easily:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::{Captures, Regex};
<span class="kw">let </span>re = Regex::new(<span class="string">r"([^,\s]+),\s+(\S+)"</span>).unwrap();
<span class="kw">let </span>result = re.replace(<span class="string">"Springsteen, Bruce"</span>, |caps: <span class="kw-2">&amp;</span>Captures| {
<span class="macro">format!</span>(<span class="string">"{} {}"</span>, <span class="kw-2">&amp;</span>caps[<span class="number">2</span>], <span class="kw-2">&amp;</span>caps[<span class="number">1</span>])
});
<span class="macro">assert_eq!</span>(result, <span class="string">"Bruce Springsteen"</span>);</code></pre></div>
<p>But this is a bit cumbersome to use all the time. Instead, a simple
syntax is supported (as described above) that expands <code>$name</code> into the
corresponding capture group. Heres the last example, but using this
expansion technique with named capture groups:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"(?&lt;last&gt;[^,\s]+),\s+(?&lt;first&gt;\S+)"</span>).unwrap();
<span class="kw">let </span>result = re.replace(<span class="string">"Springsteen, Bruce"</span>, <span class="string">"$first $last"</span>);
<span class="macro">assert_eq!</span>(result, <span class="string">"Bruce Springsteen"</span>);</code></pre></div>
<p>Note that using <code>$2</code> instead of <code>$first</code> or <code>$1</code> instead of <code>$last</code>
would produce the same result. To write a literal <code>$</code> use <code>$$</code>.</p>
<p>Sometimes the replacement string requires use of curly braces to
delineate a capture group replacement when it is adjacent to some other
literal text. For example, if we wanted to join two words together with
an underscore:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"(?&lt;first&gt;\w+)\s+(?&lt;second&gt;\w+)"</span>).unwrap();
<span class="kw">let </span>result = re.replace(<span class="string">"deep fried"</span>, <span class="string">"${first}_$second"</span>);
<span class="macro">assert_eq!</span>(result, <span class="string">"deep_fried"</span>);</code></pre></div>
<p>Without the curly braces, the capture group name <code>first_</code> would be
used, and since it doesnt exist, it would be replaced with the empty
string.</p>
<p>Finally, sometimes you just want to replace a literal string with no
regard for capturing group expansion. This can be done by wrapping a
string with <a href="struct.NoExpand.html" title="struct regex::NoExpand"><code>NoExpand</code></a>:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::{NoExpand, Regex};
<span class="kw">let </span>re = Regex::new(<span class="string">r"(?&lt;last&gt;[^,\s]+),\s+(\S+)"</span>).unwrap();
<span class="kw">let </span>result = re.replace(<span class="string">"Springsteen, Bruce"</span>, NoExpand(<span class="string">"$2 $last"</span>));
<span class="macro">assert_eq!</span>(result, <span class="string">"$2 $last"</span>);</code></pre></div>
<p>Using <code>NoExpand</code> may also be faster, since the replacement string wont
need to be parsed for the <code>$</code> syntax.</p>
</div></details><details class="toggle method-toggle" open><summary><section id="method.replace_all" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#842-848">source</a><h4 class="code-header">pub fn <a href="#method.replace_all" class="fn">replace_all</a>&lt;'h, R: <a class="trait" href="trait.Replacer.html" title="trait regex::Replacer">Replacer</a>&gt;(
&amp;self,
haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>,
rep: R,
) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/alloc/borrow/enum.Cow.html" title="enum alloc::borrow::Cow">Cow</a>&lt;'h, <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>&gt;</h4></section></summary><div class="docblock"><p>Replaces all non-overlapping matches in the haystack with the
replacement provided. This is the same as calling <code>replacen</code> with
<code>limit</code> set to <code>0</code>.</p>
<p>If no match is found, then the haystack is returned unchanged. In that
case, this implementation will likely return a <code>Cow::Borrowed</code> value
such that no allocation is performed.</p>
<p>When a <code>Cow::Borrowed</code> is returned, the value returned is guaranteed
to be equivalent to the <code>haystack</code> given.</p>
<p>The documentation for <a href="struct.Regex.html#method.replace" title="method regex::Regex::replace"><code>Regex::replace</code></a> goes into more detail about
what kinds of replacement strings are supported.</p>
<h5 id="time-complexity-4"><a class="doc-anchor" href="#time-complexity-4">§</a>Time complexity</h5>
<p>Since iterators over all matches requires running potentially many
searches on the haystack, and since each search has worst case
<code>O(m * n)</code> time complexity, the overall worst case time complexity for
this routine is <code>O(m * n^2)</code>.</p>
<h5 id="fallibility"><a class="doc-anchor" href="#fallibility">§</a>Fallibility</h5>
<p>If you need to write a replacement routine where any individual
replacement might “fail,” doing so with this API isnt really feasible
because theres no way to stop the search process if a replacement
fails. Instead, if you need this functionality, you should consider
implementing your own replacement routine:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::{Captures, Regex};
<span class="kw">fn </span>replace_all&lt;E&gt;(
re: <span class="kw-2">&amp;</span>Regex,
haystack: <span class="kw-2">&amp;</span>str,
replacement: <span class="kw">impl </span>Fn(<span class="kw-2">&amp;</span>Captures) -&gt; <span class="prelude-ty">Result</span>&lt;String, E&gt;,
) -&gt; <span class="prelude-ty">Result</span>&lt;String, E&gt; {
<span class="kw">let </span><span class="kw-2">mut </span>new = String::with_capacity(haystack.len());
<span class="kw">let </span><span class="kw-2">mut </span>last_match = <span class="number">0</span>;
<span class="kw">for </span>caps <span class="kw">in </span>re.captures_iter(haystack) {
<span class="kw">let </span>m = caps.get(<span class="number">0</span>).unwrap();
new.push_str(<span class="kw-2">&amp;</span>haystack[last_match..m.start()]);
new.push_str(<span class="kw-2">&amp;</span>replacement(<span class="kw-2">&amp;</span>caps)<span class="question-mark">?</span>);
last_match = m.end();
}
new.push_str(<span class="kw-2">&amp;</span>haystack[last_match..]);
<span class="prelude-val">Ok</span>(new)
}
<span class="comment">// Let's replace each word with the number of bytes in that word.
// But if we see a word that is "too long," we'll give up.
</span><span class="kw">let </span>re = Regex::new(<span class="string">r"\w+"</span>).unwrap();
<span class="kw">let </span>replacement = |caps: <span class="kw-2">&amp;</span>Captures| -&gt; <span class="prelude-ty">Result</span>&lt;String, <span class="kw-2">&amp;</span><span class="lifetime">'static </span>str&gt; {
<span class="kw">if </span>caps[<span class="number">0</span>].len() &gt;= <span class="number">5 </span>{
<span class="kw">return </span><span class="prelude-val">Err</span>(<span class="string">"word too long"</span>);
}
<span class="prelude-val">Ok</span>(caps[<span class="number">0</span>].len().to_string())
};
<span class="macro">assert_eq!</span>(
<span class="prelude-val">Ok</span>(<span class="string">"2 3 3 3?"</span>.to_string()),
replace_all(<span class="kw-2">&amp;</span>re, <span class="string">"hi how are you?"</span>, <span class="kw-2">&amp;</span>replacement),
);
<span class="macro">assert!</span>(replace_all(<span class="kw-2">&amp;</span>re, <span class="string">"hi there"</span>, <span class="kw-2">&amp;</span>replacement).is_err());</code></pre></div>
<h5 id="example-10"><a class="doc-anchor" href="#example-10">§</a>Example</h5>
<p>This example shows how to flip the order of whitespace (excluding line
terminators) delimited fields, and normalizes the whitespace that
delimits the fields:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"(?m)^(\S+)[\s--\r\n]+(\S+)$"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"
Greetings 1973
Wild\t1973
BornToRun\t\t\t\t1975
Darkness 1978
TheRiver 1980
"</span>;
<span class="kw">let </span>new = re.replace_all(hay, <span class="string">"$2 $1"</span>);
<span class="macro">assert_eq!</span>(new, <span class="string">"
1973 Greetings
1973 Wild
1975 BornToRun
1978 Darkness
1980 TheRiver
"</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.replacen" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#907-961">source</a><h4 class="code-header">pub fn <a href="#method.replacen" class="fn">replacen</a>&lt;'h, R: <a class="trait" href="trait.Replacer.html" title="trait regex::Replacer">Replacer</a>&gt;(
&amp;self,
haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>,
limit: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>,
rep: R,
) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/alloc/borrow/enum.Cow.html" title="enum alloc::borrow::Cow">Cow</a>&lt;'h, <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>&gt;</h4></section></summary><div class="docblock"><p>Replaces at most <code>limit</code> non-overlapping matches in the haystack with
the replacement provided. If <code>limit</code> is <code>0</code>, then all non-overlapping
matches are replaced. That is, <code>Regex::replace_all(hay, rep)</code> is
equivalent to <code>Regex::replacen(hay, 0, rep)</code>.</p>
<p>If no match is found, then the haystack is returned unchanged. In that
case, this implementation will likely return a <code>Cow::Borrowed</code> value
such that no allocation is performed.</p>
<p>When a <code>Cow::Borrowed</code> is returned, the value returned is guaranteed
to be equivalent to the <code>haystack</code> given.</p>
<p>The documentation for <a href="struct.Regex.html#method.replace" title="method regex::Regex::replace"><code>Regex::replace</code></a> goes into more detail about
what kinds of replacement strings are supported.</p>
<h5 id="time-complexity-5"><a class="doc-anchor" href="#time-complexity-5">§</a>Time complexity</h5>
<p>Since iterators over all matches requires running potentially many
searches on the haystack, and since each search has worst case
<code>O(m * n)</code> time complexity, the overall worst case time complexity for
this routine is <code>O(m * n^2)</code>.</p>
<p>Although note that the worst case time here has an upper bound given
by the <code>limit</code> parameter.</p>
<h5 id="fallibility-1"><a class="doc-anchor" href="#fallibility-1">§</a>Fallibility</h5>
<p>See the corresponding section in the docs for <a href="struct.Regex.html#method.replace_all" title="method regex::Regex::replace_all"><code>Regex::replace_all</code></a>
for tips on how to deal with a replacement routine that can fail.</p>
<h5 id="example-11"><a class="doc-anchor" href="#example-11">§</a>Example</h5>
<p>This example shows how to flip the order of whitespace (excluding line
terminators) delimited fields, and normalizes the whitespace that
delimits the fields. But we only do it for the first two matches.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"(?m)^(\S+)[\s--\r\n]+(\S+)$"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"
Greetings 1973
Wild\t1973
BornToRun\t\t\t\t1975
Darkness 1978
TheRiver 1980
"</span>;
<span class="kw">let </span>new = re.replacen(hay, <span class="number">2</span>, <span class="string">"$2 $1"</span>);
<span class="macro">assert_eq!</span>(new, <span class="string">"
1973 Greetings
1973 Wild
BornToRun\t\t\t\t1975
Darkness 1978
TheRiver 1980
"</span>);</code></pre></div>
</div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-Regex-1" class="impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#968-1260">source</a><a href="#impl-Regex-1" class="anchor">§</a><h3 class="code-header">impl <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section></summary><div class="docblock"><p>A group of advanced or “lower level” search methods. Some methods permit
starting the search at a position greater than <code>0</code> in the haystack. Other
methods permit reusing allocations, for example, when extracting the
matches for capture groups.</p>
</div><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.shortest_match" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#998-1000">source</a><h4 class="code-header">pub fn <a href="#method.shortest_match" class="fn">shortest_match</a>(&amp;self, haystack: &amp;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>&gt;</h4></section></summary><div class="docblock"><p>Returns the end byte offset of the first match in the haystack given.</p>
<p>This method may have the same performance characteristics as
<code>is_match</code>. Behaviorlly, it doesnt just report whether it match
occurs, but also the end offset for a match. In particular, the offset
returned <em>may be shorter</em> than the proper end of the leftmost-first
match that you would find via <a href="struct.Regex.html#method.find" title="method regex::Regex::find"><code>Regex::find</code></a>.</p>
<p>Note that it is not guaranteed that this routine finds the shortest or
“earliest” possible match. Instead, the main idea of this API is that
it returns the offset at the point at which the internal regex engine
has determined that a match has occurred. This may vary depending on
which internal regex engine is used, and thus, the offset itself may
change based on internal heuristics.</p>
<h5 id="example-12"><a class="doc-anchor" href="#example-12">§</a>Example</h5>
<p>Typically, <code>a+</code> would match the entire first sequence of <code>a</code> in some
haystack, but <code>shortest_match</code> <em>may</em> give up as soon as it sees the
first <code>a</code>.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"a+"</span>).unwrap();
<span class="kw">let </span>offset = re.shortest_match(<span class="string">"aaaaa"</span>).unwrap();
<span class="macro">assert_eq!</span>(offset, <span class="number">1</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.shortest_match_at" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1033-1041">source</a><h4 class="code-header">pub fn <a href="#method.shortest_match_at" class="fn">shortest_match_at</a>(&amp;self, haystack: &amp;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>, start: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>&gt;</h4></section></summary><div class="docblock"><p>Returns the same as <a href="struct.Regex.html#method.shortest_match" title="method regex::Regex::shortest_match"><code>Regex::shortest_match</code></a>, but starts the search at
the given offset.</p>
<p>The significance of the starting point is that it takes the surrounding
context into consideration. For example, the <code>\A</code> anchor can only match
when <code>start == 0</code>.</p>
<p>If a match is found, the offset returned is relative to the beginning
of the haystack, not the beginning of the search.</p>
<h5 id="panics"><a class="doc-anchor" href="#panics">§</a>Panics</h5>
<p>This panics when <code>start &gt;= haystack.len() + 1</code>.</p>
<h5 id="example-13"><a class="doc-anchor" href="#example-13">§</a>Example</h5>
<p>This example shows the significance of <code>start</code> by demonstrating how it
can be used to permit look-around assertions in a regex to take the
surrounding context into account.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"\bchew\b"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"eschew"</span>;
<span class="comment">// We get a match here, but it's probably not intended.
</span><span class="macro">assert_eq!</span>(re.shortest_match(<span class="kw-2">&amp;</span>hay[<span class="number">2</span>..]), <span class="prelude-val">Some</span>(<span class="number">4</span>));
<span class="comment">// No match because the assertions take the context into account.
</span><span class="macro">assert_eq!</span>(re.shortest_match_at(hay, <span class="number">2</span>), <span class="prelude-val">None</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.is_match_at" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1071-1075">source</a><h4 class="code-header">pub fn <a href="#method.is_match_at" class="fn">is_match_at</a>(&amp;self, haystack: &amp;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>, start: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.bool.html">bool</a></h4></section></summary><div class="docblock"><p>Returns the same as <a href="struct.Regex.html#method.is_match" title="method regex::Regex::is_match"><code>Regex::is_match</code></a>, but starts the search at the
given offset.</p>
<p>The significance of the starting point is that it takes the surrounding
context into consideration. For example, the <code>\A</code> anchor can only
match when <code>start == 0</code>.</p>
<h5 id="panics-1"><a class="doc-anchor" href="#panics-1">§</a>Panics</h5>
<p>This panics when <code>start &gt;= haystack.len() + 1</code>.</p>
<h5 id="example-14"><a class="doc-anchor" href="#example-14">§</a>Example</h5>
<p>This example shows the significance of <code>start</code> by demonstrating how it
can be used to permit look-around assertions in a regex to take the
surrounding context into account.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"\bchew\b"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"eschew"</span>;
<span class="comment">// We get a match here, but it's probably not intended.
</span><span class="macro">assert!</span>(re.is_match(<span class="kw-2">&amp;</span>hay[<span class="number">2</span>..]));
<span class="comment">// No match because the assertions take the context into account.
</span><span class="macro">assert!</span>(!re.is_match_at(hay, <span class="number">2</span>));</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.find_at" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1105-1114">source</a><h4 class="code-header">pub fn <a href="#method.find_at" class="fn">find_at</a>&lt;'h&gt;(&amp;self, haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>, start: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="struct.Match.html" title="struct regex::Match">Match</a>&lt;'h&gt;&gt;</h4></section></summary><div class="docblock"><p>Returns the same as <a href="struct.Regex.html#method.find" title="method regex::Regex::find"><code>Regex::find</code></a>, but starts the search at the given
offset.</p>
<p>The significance of the starting point is that it takes the surrounding
context into consideration. For example, the <code>\A</code> anchor can only
match when <code>start == 0</code>.</p>
<h5 id="panics-2"><a class="doc-anchor" href="#panics-2">§</a>Panics</h5>
<p>This panics when <code>start &gt;= haystack.len() + 1</code>.</p>
<h5 id="example-15"><a class="doc-anchor" href="#example-15">§</a>Example</h5>
<p>This example shows the significance of <code>start</code> by demonstrating how it
can be used to permit look-around assertions in a regex to take the
surrounding context into account.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"\bchew\b"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"eschew"</span>;
<span class="comment">// We get a match here, but it's probably not intended.
</span><span class="macro">assert_eq!</span>(re.find(<span class="kw-2">&amp;</span>hay[<span class="number">2</span>..]).map(|m| m.range()), <span class="prelude-val">Some</span>(<span class="number">0</span>..<span class="number">4</span>));
<span class="comment">// No match because the assertions take the context into account.
</span><span class="macro">assert_eq!</span>(re.find_at(hay, <span class="number">2</span>), <span class="prelude-val">None</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.captures_at" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1144-1158">source</a><h4 class="code-header">pub fn <a href="#method.captures_at" class="fn">captures_at</a>&lt;'h&gt;(
&amp;self,
haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>,
start: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>,
) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="struct.Captures.html" title="struct regex::Captures">Captures</a>&lt;'h&gt;&gt;</h4></section></summary><div class="docblock"><p>Returns the same as <a href="struct.Regex.html#method.captures" title="method regex::Regex::captures"><code>Regex::captures</code></a>, but starts the search at the
given offset.</p>
<p>The significance of the starting point is that it takes the surrounding
context into consideration. For example, the <code>\A</code> anchor can only
match when <code>start == 0</code>.</p>
<h5 id="panics-3"><a class="doc-anchor" href="#panics-3">§</a>Panics</h5>
<p>This panics when <code>start &gt;= haystack.len() + 1</code>.</p>
<h5 id="example-16"><a class="doc-anchor" href="#example-16">§</a>Example</h5>
<p>This example shows the significance of <code>start</code> by demonstrating how it
can be used to permit look-around assertions in a regex to take the
surrounding context into account.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"\bchew\b"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"eschew"</span>;
<span class="comment">// We get a match here, but it's probably not intended.
</span><span class="macro">assert_eq!</span>(<span class="kw-2">&amp;</span>re.captures(<span class="kw-2">&amp;</span>hay[<span class="number">2</span>..]).unwrap()[<span class="number">0</span>], <span class="string">"chew"</span>);
<span class="comment">// No match because the assertions take the context into account.
</span><span class="macro">assert!</span>(re.captures_at(hay, <span class="number">2</span>).is_none());</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.captures_read" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1194-1200">source</a><h4 class="code-header">pub fn <a href="#method.captures_read" class="fn">captures_read</a>&lt;'h&gt;(
&amp;self,
locs: &amp;mut <a class="struct" href="struct.CaptureLocations.html" title="struct regex::CaptureLocations">CaptureLocations</a>,
haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>,
) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="struct.Match.html" title="struct regex::Match">Match</a>&lt;'h&gt;&gt;</h4></section></summary><div class="docblock"><p>This is like <a href="struct.Regex.html#method.captures" title="method regex::Regex::captures"><code>Regex::captures</code></a>, but writes the byte offsets of each
capture group match into the locations given.</p>
<p>A <a href="struct.CaptureLocations.html" title="struct regex::CaptureLocations"><code>CaptureLocations</code></a> stores the same byte offsets as a <a href="struct.Captures.html" title="struct regex::Captures"><code>Captures</code></a>,
but does <em>not</em> store a reference to the haystack. This makes its API
a bit lower level and less convenient. But in exchange, callers
may allocate their own <code>CaptureLocations</code> and reuse it for multiple
searches. This may be helpful if allocating a <code>Captures</code> shows up in a
profile as too costly.</p>
<p>To create a <code>CaptureLocations</code> value, use the
<a href="struct.Regex.html#method.capture_locations" title="method regex::Regex::capture_locations"><code>Regex::capture_locations</code></a> method.</p>
<p>This also returns the overall match if one was found. When a match is
found, its offsets are also always stored in <code>locs</code> at index <code>0</code>.</p>
<h5 id="panics-4"><a class="doc-anchor" href="#panics-4">§</a>Panics</h5>
<p>This routine may panic if the given <code>CaptureLocations</code> was not created
by this regex.</p>
<h5 id="example-17"><a class="doc-anchor" href="#example-17">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"^([a-z]+)=(\S*)$"</span>).unwrap();
<span class="kw">let </span><span class="kw-2">mut </span>locs = re.capture_locations();
<span class="macro">assert!</span>(re.captures_read(<span class="kw-2">&amp;mut </span>locs, <span class="string">"id=foo123"</span>).is_some());
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>((<span class="number">0</span>, <span class="number">9</span>)), locs.get(<span class="number">0</span>));
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>((<span class="number">0</span>, <span class="number">2</span>)), locs.get(<span class="number">1</span>));
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>((<span class="number">3</span>, <span class="number">9</span>)), locs.get(<span class="number">2</span>));</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.captures_read_at" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1234-1243">source</a><h4 class="code-header">pub fn <a href="#method.captures_read_at" class="fn">captures_read_at</a>&lt;'h&gt;(
&amp;self,
locs: &amp;mut <a class="struct" href="struct.CaptureLocations.html" title="struct regex::CaptureLocations">CaptureLocations</a>,
haystack: &amp;'h <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>,
start: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>,
) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="struct" href="struct.Match.html" title="struct regex::Match">Match</a>&lt;'h&gt;&gt;</h4></section></summary><div class="docblock"><p>Returns the same as <a href="struct.Regex.html#method.captures_read" title="method regex::Regex::captures_read"><code>Regex::captures_read</code></a>, but starts the search at
the given offset.</p>
<p>The significance of the starting point is that it takes the surrounding
context into consideration. For example, the <code>\A</code> anchor can only
match when <code>start == 0</code>.</p>
<h5 id="panics-5"><a class="doc-anchor" href="#panics-5">§</a>Panics</h5>
<p>This panics when <code>start &gt;= haystack.len() + 1</code>.</p>
<p>This routine may also panic if the given <code>CaptureLocations</code> was not
created by this regex.</p>
<h5 id="example-18"><a class="doc-anchor" href="#example-18">§</a>Example</h5>
<p>This example shows the significance of <code>start</code> by demonstrating how it
can be used to permit look-around assertions in a regex to take the
surrounding context into account.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"\bchew\b"</span>).unwrap();
<span class="kw">let </span>hay = <span class="string">"eschew"</span>;
<span class="kw">let </span><span class="kw-2">mut </span>locs = re.capture_locations();
<span class="comment">// We get a match here, but it's probably not intended.
</span><span class="macro">assert!</span>(re.captures_read(<span class="kw-2">&amp;mut </span>locs, <span class="kw-2">&amp;</span>hay[<span class="number">2</span>..]).is_some());
<span class="comment">// No match because the assertions take the context into account.
</span><span class="macro">assert!</span>(re.captures_read_at(<span class="kw-2">&amp;mut </span>locs, hay, <span class="number">2</span>).is_none());</code></pre></div>
</div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-Regex-2" class="impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#1263-1435">source</a><a href="#impl-Regex-2" class="anchor">§</a><h3 class="code-header">impl <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section></summary><div class="docblock"><p>Auxiliary methods.</p>
</div><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.as_str" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1275-1277">source</a><h4 class="code-header">pub fn <a href="#method.as_str" class="fn">as_str</a>(&amp;self) -&gt; &amp;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a></h4></section></summary><div class="docblock"><p>Returns the original string of this regex.</p>
<h5 id="example-19"><a class="doc-anchor" href="#example-19">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"foo\w+bar"</span>).unwrap();
<span class="macro">assert_eq!</span>(re.as_str(), <span class="string">r"foo\w+bar"</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.capture_names" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1325-1327">source</a><h4 class="code-header">pub fn <a href="#method.capture_names" class="fn">capture_names</a>(&amp;self) -&gt; <a class="struct" href="struct.CaptureNames.html" title="struct regex::CaptureNames">CaptureNames</a>&lt;'_&gt; <a href="#" class="tooltip" data-notable-ty="CaptureNames&lt;&#39;_&gt;"></a></h4></section></summary><div class="docblock"><p>Returns an iterator over the capture names in this regex.</p>
<p>The iterator returned yields elements of type <code>Option&lt;&amp;str&gt;</code>. That is,
the iterator yields values for all capture groups, even ones that are
unnamed. The order of the groups corresponds to the order of the groups
corresponding opening parenthesis.</p>
<p>The first element of the iterator always yields the group corresponding
to the overall match, and this group is always unnamed. Therefore, the
iterator always yields at least one group.</p>
<h5 id="example-20"><a class="doc-anchor" href="#example-20">§</a>Example</h5>
<p>This shows basic usage with a mix of named and unnamed capture groups:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"(?&lt;a&gt;.(?&lt;b&gt;.))(.)(?:.)(?&lt;c&gt;.)"</span>).unwrap();
<span class="kw">let </span><span class="kw-2">mut </span>names = re.capture_names();
<span class="macro">assert_eq!</span>(names.next(), <span class="prelude-val">Some</span>(<span class="prelude-val">None</span>));
<span class="macro">assert_eq!</span>(names.next(), <span class="prelude-val">Some</span>(<span class="prelude-val">Some</span>(<span class="string">"a"</span>)));
<span class="macro">assert_eq!</span>(names.next(), <span class="prelude-val">Some</span>(<span class="prelude-val">Some</span>(<span class="string">"b"</span>)));
<span class="macro">assert_eq!</span>(names.next(), <span class="prelude-val">Some</span>(<span class="prelude-val">None</span>));
<span class="comment">// the '(?:.)' group is non-capturing and so doesn't appear here!
</span><span class="macro">assert_eq!</span>(names.next(), <span class="prelude-val">Some</span>(<span class="prelude-val">Some</span>(<span class="string">"c"</span>)));
<span class="macro">assert_eq!</span>(names.next(), <span class="prelude-val">None</span>);</code></pre></div>
<p>The iterator always yields at least one element, even for regexes with
no capture groups and even for regexes that can never match:</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r""</span>).unwrap();
<span class="kw">let </span><span class="kw-2">mut </span>names = re.capture_names();
<span class="macro">assert_eq!</span>(names.next(), <span class="prelude-val">Some</span>(<span class="prelude-val">None</span>));
<span class="macro">assert_eq!</span>(names.next(), <span class="prelude-val">None</span>);
<span class="kw">let </span>re = Regex::new(<span class="string">r"[a&amp;&amp;b]"</span>).unwrap();
<span class="kw">let </span><span class="kw-2">mut </span>names = re.capture_names();
<span class="macro">assert_eq!</span>(names.next(), <span class="prelude-val">Some</span>(<span class="prelude-val">None</span>));
<span class="macro">assert_eq!</span>(names.next(), <span class="prelude-val">None</span>);</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.captures_len" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1356-1358">source</a><h4 class="code-header">pub fn <a href="#method.captures_len" class="fn">captures_len</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a></h4></section></summary><div class="docblock"><p>Returns the number of captures groups in this regex.</p>
<p>This includes all named and unnamed groups, including the implicit
unnamed group that is always present and corresponds to the entire
match.</p>
<p>Since the implicit unnamed group is always included in this length, the
length returned is guaranteed to be greater than zero.</p>
<h5 id="example-21"><a class="doc-anchor" href="#example-21">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"foo"</span>).unwrap();
<span class="macro">assert_eq!</span>(<span class="number">1</span>, re.captures_len());
<span class="kw">let </span>re = Regex::new(<span class="string">r"(foo)"</span>).unwrap();
<span class="macro">assert_eq!</span>(<span class="number">2</span>, re.captures_len());
<span class="kw">let </span>re = Regex::new(<span class="string">r"(?&lt;a&gt;.(?&lt;b&gt;.))(.)(?:.)(?&lt;c&gt;.)"</span>).unwrap();
<span class="macro">assert_eq!</span>(<span class="number">5</span>, re.captures_len());
<span class="kw">let </span>re = Regex::new(<span class="string">r"[a&amp;&amp;b]"</span>).unwrap();
<span class="macro">assert_eq!</span>(<span class="number">1</span>, re.captures_len());</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.static_captures_len" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1396-1398">source</a><h4 class="code-header">pub fn <a href="#method.static_captures_len" class="fn">static_captures_len</a>(&amp;self) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.usize.html">usize</a>&gt;</h4></section></summary><div class="docblock"><p>Returns the total number of capturing groups that appear in every
possible match.</p>
<p>If the number of capture groups can vary depending on the match, then
this returns <code>None</code>. That is, a value is only returned when the number
of matching groups is invariant or “static.”</p>
<p>Note that like <a href="struct.Regex.html#method.captures_len" title="method regex::Regex::captures_len"><code>Regex::captures_len</code></a>, this <strong>does</strong> include the
implicit capturing group corresponding to the entire match. Therefore,
when a non-None value is returned, it is guaranteed to be at least <code>1</code>.
Stated differently, a return value of <code>Some(0)</code> is impossible.</p>
<h5 id="example-22"><a class="doc-anchor" href="#example-22">§</a>Example</h5>
<p>This shows a few cases where a static number of capture groups is
available and a few cases where it is not.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>len = |pattern| {
Regex::new(pattern).map(|re| re.static_captures_len())
};
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">1</span>), len(<span class="string">"a"</span>)<span class="question-mark">?</span>);
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">2</span>), len(<span class="string">"(a)"</span>)<span class="question-mark">?</span>);
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">2</span>), len(<span class="string">"(a)|(b)"</span>)<span class="question-mark">?</span>);
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">3</span>), len(<span class="string">"(a)(b)|(c)(d)"</span>)<span class="question-mark">?</span>);
<span class="macro">assert_eq!</span>(<span class="prelude-val">None</span>, len(<span class="string">"(a)|b"</span>)<span class="question-mark">?</span>);
<span class="macro">assert_eq!</span>(<span class="prelude-val">None</span>, len(<span class="string">"a|(b)"</span>)<span class="question-mark">?</span>);
<span class="macro">assert_eq!</span>(<span class="prelude-val">None</span>, len(<span class="string">"(b)*"</span>)<span class="question-mark">?</span>);
<span class="macro">assert_eq!</span>(<span class="prelude-val">Some</span>(<span class="number">2</span>), len(<span class="string">"(b)+"</span>)<span class="question-mark">?</span>);
</code></pre></div>
</div></details><details class="toggle method-toggle" open><summary><section id="method.capture_locations" class="method"><a class="src rightside" href="../src/regex/regex/string.rs.html#1422-1424">source</a><h4 class="code-header">pub fn <a href="#method.capture_locations" class="fn">capture_locations</a>(&amp;self) -&gt; <a class="struct" href="struct.CaptureLocations.html" title="struct regex::CaptureLocations">CaptureLocations</a></h4></section></summary><div class="docblock"><p>Returns a fresh allocated set of capture locations that can
be reused in multiple calls to <a href="struct.Regex.html#method.captures_read" title="method regex::Regex::captures_read"><code>Regex::captures_read</code></a> or
<a href="struct.Regex.html#method.captures_read_at" title="method regex::Regex::captures_read_at"><code>Regex::captures_read_at</code></a>.</p>
<p>The returned locations can be used for any subsequent search for this
particular regex. There is no guarantee that it is correct to use for
other regexes, even if they have the same number of capture groups.</p>
<h5 id="example-23"><a class="doc-anchor" href="#example-23">§</a>Example</h5>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>regex::Regex;
<span class="kw">let </span>re = Regex::new(<span class="string">r"(.)(.)(\w+)"</span>).unwrap();
<span class="kw">let </span><span class="kw-2">mut </span>locs = re.capture_locations();
<span class="macro">assert!</span>(re.captures_read(<span class="kw-2">&amp;mut </span>locs, <span class="string">"Padron"</span>).is_some());
<span class="macro">assert_eq!</span>(locs.get(<span class="number">0</span>), <span class="prelude-val">Some</span>((<span class="number">0</span>, <span class="number">6</span>)));
<span class="macro">assert_eq!</span>(locs.get(<span class="number">1</span>), <span class="prelude-val">Some</span>((<span class="number">0</span>, <span class="number">1</span>)));
<span class="macro">assert_eq!</span>(locs.get(<span class="number">2</span>), <span class="prelude-val">Some</span>((<span class="number">1</span>, <span class="number">2</span>)));
<span class="macro">assert_eq!</span>(locs.get(<span class="number">3</span>), <span class="prelude-val">Some</span>((<span class="number">2</span>, <span class="number">6</span>)));</code></pre></div>
</div></details></div></details></div><h2 id="trait-implementations" class="section-header">Trait Implementations<a href="#trait-implementations" class="anchor">§</a></h2><div id="trait-implementations-list"><details class="toggle implementors-toggle" open><summary><section id="impl-Clone-for-Regex" class="impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#100">source</a><a href="#impl-Clone-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a> for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.clone" class="method trait-impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#100">source</a><a href="#method.clone" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/clone/trait.Clone.html#tymethod.clone" class="fn">clone</a>(&amp;self) -&gt; <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h4></section></summary><div class='docblock'>Returns a copy of the value. <a href="https://doc.rust-lang.org/1.80.0/core/clone/trait.Clone.html#tymethod.clone">Read more</a></div></details><details class="toggle method-toggle" open><summary><section id="method.clone_from" class="method trait-impl"><span class="rightside"><span class="since" title="Stable since Rust version 1.0.0">1.0.0</span> · <a class="src" href="https://doc.rust-lang.org/1.80.0/src/core/clone.rs.html#169">source</a></span><a href="#method.clone_from" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/clone/trait.Clone.html#method.clone_from" class="fn">clone_from</a>(&amp;mut self, source: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.reference.html">&amp;Self</a>)</h4></section></summary><div class='docblock'>Performs copy-assignment from <code>source</code>. <a href="https://doc.rust-lang.org/1.80.0/core/clone/trait.Clone.html#method.clone_from">Read more</a></div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-Debug-for-Regex" class="impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#113-118">source</a><a href="#impl-Debug-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a> for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.fmt" class="method trait-impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#115-117">source</a><a href="#method.fmt" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/fmt/trait.Debug.html#tymethod.fmt" class="fn">fmt</a>(&amp;self, f: &amp;mut <a class="struct" href="https://doc.rust-lang.org/1.80.0/core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a>&lt;'_&gt;) -&gt; <a class="type" href="https://doc.rust-lang.org/1.80.0/core/fmt/type.Result.html" title="type core::fmt::Result">Result</a></h4></section></summary><div class="docblock"><p>Shows the original regular expression.</p>
</div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-Display-for-Regex" class="impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#106-111">source</a><a href="#impl-Display-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/fmt/trait.Display.html" title="trait core::fmt::Display">Display</a> for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.fmt-1" class="method trait-impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#108-110">source</a><a href="#method.fmt-1" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/fmt/trait.Display.html#tymethod.fmt" class="fn">fmt</a>(&amp;self, f: &amp;mut <a class="struct" href="https://doc.rust-lang.org/1.80.0/core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a>&lt;'_&gt;) -&gt; <a class="type" href="https://doc.rust-lang.org/1.80.0/core/fmt/type.Result.html" title="type core::fmt::Result">Result</a></h4></section></summary><div class="docblock"><p>Shows the original regular expression.</p>
</div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-FromStr-for-Regex" class="impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#120-127">source</a><a href="#impl-FromStr-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/str/traits/trait.FromStr.html" title="trait core::str::traits::FromStr">FromStr</a> for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.from_str" class="method trait-impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#124-126">source</a><a href="#method.from_str" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/str/traits/trait.FromStr.html#tymethod.from_str" class="fn">from_str</a>(s: &amp;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a>, <a class="enum" href="enum.Error.html" title="enum regex::Error">Error</a>&gt;</h4></section></summary><div class="docblock"><p>Attempts to parse a string into a regular expression</p>
</div></details><details class="toggle" open><summary><section id="associatedtype.Err" class="associatedtype trait-impl"><a href="#associatedtype.Err" class="anchor">§</a><h4 class="code-header">type <a href="https://doc.rust-lang.org/1.80.0/core/str/traits/trait.FromStr.html#associatedtype.Err" class="associatedtype">Err</a> = <a class="enum" href="enum.Error.html" title="enum regex::Error">Error</a></h4></section></summary><div class='docblock'>The associated error which can be returned from parsing.</div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-TryFrom%3C%26str%3E-for-Regex" class="impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#129-136">source</a><a href="#impl-TryFrom%3C%26str%3E-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;&amp;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>&gt; for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.try_from-1" class="method trait-impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#133-135">source</a><a href="#method.try_from-1" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html#tymethod.try_from" class="fn">try_from</a>(s: &amp;<a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.str.html">str</a>) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a>, <a class="enum" href="enum.Error.html" title="enum regex::Error">Error</a>&gt;</h4></section></summary><div class="docblock"><p>Attempts to parse a string into a regular expression</p>
</div></details><details class="toggle" open><summary><section id="associatedtype.Error-1" class="associatedtype trait-impl"><a href="#associatedtype.Error-1" class="anchor">§</a><h4 class="code-header">type <a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html#associatedtype.Error" class="associatedtype">Error</a> = <a class="enum" href="enum.Error.html" title="enum regex::Error">Error</a></h4></section></summary><div class='docblock'>The type returned in the event of a conversion error.</div></details></div></details><details class="toggle implementors-toggle" open><summary><section id="impl-TryFrom%3CString%3E-for-Regex" class="impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#138-145">source</a><a href="#impl-TryFrom%3CString%3E-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;<a class="struct" href="https://doc.rust-lang.org/1.80.0/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>&gt; for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.try_from" class="method trait-impl"><a class="src rightside" href="../src/regex/regex/string.rs.html#142-144">source</a><a href="#method.try_from" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html#tymethod.try_from" class="fn">try_from</a>(s: <a class="struct" href="https://doc.rust-lang.org/1.80.0/alloc/string/struct.String.html" title="struct alloc::string::String">String</a>) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;<a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a>, <a class="enum" href="enum.Error.html" title="enum regex::Error">Error</a>&gt;</h4></section></summary><div class="docblock"><p>Attempts to parse a string into a regular expression</p>
</div></details><details class="toggle" open><summary><section id="associatedtype.Error" class="associatedtype trait-impl"><a href="#associatedtype.Error" class="anchor">§</a><h4 class="code-header">type <a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html#associatedtype.Error" class="associatedtype">Error</a> = <a class="enum" href="enum.Error.html" title="enum regex::Error">Error</a></h4></section></summary><div class='docblock'>The type returned in the event of a conversion error.</div></details></div></details></div><h2 id="synthetic-implementations" class="section-header">Auto Trait Implementations<a href="#synthetic-implementations" class="anchor">§</a></h2><div id="synthetic-implementations-list"><section id="impl-Freeze-for-Regex" class="impl"><a href="#impl-Freeze-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/marker/trait.Freeze.html" title="trait core::marker::Freeze">Freeze</a> for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section><section id="impl-RefUnwindSafe-for-Regex" class="impl"><a href="#impl-RefUnwindSafe-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/panic/unwind_safe/trait.RefUnwindSafe.html" title="trait core::panic::unwind_safe::RefUnwindSafe">RefUnwindSafe</a> for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section><section id="impl-Send-for-Regex" class="impl"><a href="#impl-Send-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/marker/trait.Send.html" title="trait core::marker::Send">Send</a> for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section><section id="impl-Sync-for-Regex" class="impl"><a href="#impl-Sync-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/marker/trait.Sync.html" title="trait core::marker::Sync">Sync</a> for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section><section id="impl-Unpin-for-Regex" class="impl"><a href="#impl-Unpin-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/marker/trait.Unpin.html" title="trait core::marker::Unpin">Unpin</a> for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section><section id="impl-UnwindSafe-for-Regex" class="impl"><a href="#impl-UnwindSafe-for-Regex" class="anchor">§</a><h3 class="code-header">impl <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/panic/unwind_safe/trait.UnwindSafe.html" title="trait core::panic::unwind_safe::UnwindSafe">UnwindSafe</a> for <a class="struct" href="struct.Regex.html" title="struct regex::Regex">Regex</a></h3></section></div><h2 id="blanket-implementations" class="section-header">Blanket Implementations<a href="#blanket-implementations" class="anchor">§</a></h2><div id="blanket-implementations-list"><details class="toggle implementors-toggle"><summary><section id="impl-Any-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/any.rs.html#140">source</a><a href="#impl-Any-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/any/trait.Any.html" title="trait core::any::Any">Any</a> for T<div class="where">where
T: 'static + ?<a class="trait" href="https://doc.rust-lang.org/1.80.0/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</div></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.type_id" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/any.rs.html#141">source</a><a href="#method.type_id" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/any/trait.Any.html#tymethod.type_id" class="fn">type_id</a>(&amp;self) -&gt; <a class="struct" href="https://doc.rust-lang.org/1.80.0/core/any/struct.TypeId.html" title="struct core::any::TypeId">TypeId</a></h4></section></summary><div class='docblock'>Gets the <code>TypeId</code> of <code>self</code>. <a href="https://doc.rust-lang.org/1.80.0/core/any/trait.Any.html#tymethod.type_id">Read more</a></div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-Borrow%3CT%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/borrow.rs.html#208">source</a><a href="#impl-Borrow%3CT%3E-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/borrow/trait.Borrow.html" title="trait core::borrow::Borrow">Borrow</a>&lt;T&gt; for T<div class="where">where
T: ?<a class="trait" href="https://doc.rust-lang.org/1.80.0/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</div></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.borrow" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/borrow.rs.html#210">source</a><a href="#method.borrow" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/borrow/trait.Borrow.html#tymethod.borrow" class="fn">borrow</a>(&amp;self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.reference.html">&amp;T</a></h4></section></summary><div class='docblock'>Immutably borrows from an owned value. <a href="https://doc.rust-lang.org/1.80.0/core/borrow/trait.Borrow.html#tymethod.borrow">Read more</a></div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-BorrowMut%3CT%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/borrow.rs.html#216">source</a><a href="#impl-BorrowMut%3CT%3E-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/borrow/trait.BorrowMut.html" title="trait core::borrow::BorrowMut">BorrowMut</a>&lt;T&gt; for T<div class="where">where
T: ?<a class="trait" href="https://doc.rust-lang.org/1.80.0/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</div></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.borrow_mut" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/borrow.rs.html#217">source</a><a href="#method.borrow_mut" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/borrow/trait.BorrowMut.html#tymethod.borrow_mut" class="fn">borrow_mut</a>(&amp;mut self) -&gt; <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.reference.html">&amp;mut T</a></h4></section></summary><div class='docblock'>Mutably borrows from an owned value. <a href="https://doc.rust-lang.org/1.80.0/core/borrow/trait.BorrowMut.html#tymethod.borrow_mut">Read more</a></div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-From%3CT%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/convert/mod.rs.html#765">source</a><a href="#impl-From%3CT%3E-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.From.html" title="trait core::convert::From">From</a>&lt;T&gt; for T</h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.from" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/convert/mod.rs.html#768">source</a><a href="#method.from" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.From.html#tymethod.from" class="fn">from</a>(t: T) -&gt; T</h4></section></summary><div class="docblock"><p>Returns the argument unchanged.</p>
</div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-Into%3CU%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/convert/mod.rs.html#748-750">source</a><a href="#impl-Into%3CU%3E-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T, U&gt; <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a>&lt;U&gt; for T<div class="where">where
U: <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.From.html" title="trait core::convert::From">From</a>&lt;T&gt;,</div></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.into" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/convert/mod.rs.html#758">source</a><a href="#method.into" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.Into.html#tymethod.into" class="fn">into</a>(self) -&gt; U</h4></section></summary><div class="docblock"><p>Calls <code>U::from(self)</code>.</p>
<p>That is, this conversion is whatever the implementation of
<code><a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.From.html" title="trait core::convert::From">From</a>&lt;T&gt; for U</code> chooses to do.</p>
</div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-ToOwned-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/alloc/borrow.rs.html#83-85">source</a><a href="#impl-ToOwned-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.80.0/alloc/borrow/trait.ToOwned.html" title="trait alloc::borrow::ToOwned">ToOwned</a> for T<div class="where">where
T: <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>,</div></h3></section></summary><div class="impl-items"><details class="toggle" open><summary><section id="associatedtype.Owned" class="associatedtype trait-impl"><a href="#associatedtype.Owned" class="anchor">§</a><h4 class="code-header">type <a href="https://doc.rust-lang.org/1.80.0/alloc/borrow/trait.ToOwned.html#associatedtype.Owned" class="associatedtype">Owned</a> = T</h4></section></summary><div class='docblock'>The resulting type after obtaining ownership.</div></details><details class="toggle method-toggle" open><summary><section id="method.to_owned" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/alloc/borrow.rs.html#88">source</a><a href="#method.to_owned" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/alloc/borrow/trait.ToOwned.html#tymethod.to_owned" class="fn">to_owned</a>(&amp;self) -&gt; T</h4></section></summary><div class='docblock'>Creates owned data from borrowed data, usually by cloning. <a href="https://doc.rust-lang.org/1.80.0/alloc/borrow/trait.ToOwned.html#tymethod.to_owned">Read more</a></div></details><details class="toggle method-toggle" open><summary><section id="method.clone_into" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/alloc/borrow.rs.html#92">source</a><a href="#method.clone_into" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/alloc/borrow/trait.ToOwned.html#method.clone_into" class="fn">clone_into</a>(&amp;self, target: <a class="primitive" href="https://doc.rust-lang.org/1.80.0/std/primitive.reference.html">&amp;mut T</a>)</h4></section></summary><div class='docblock'>Uses borrowed data to replace owned data, usually by cloning. <a href="https://doc.rust-lang.org/1.80.0/alloc/borrow/trait.ToOwned.html#method.clone_into">Read more</a></div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-ToString-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/alloc/string.rs.html#2552">source</a><a href="#impl-ToString-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="https://doc.rust-lang.org/1.80.0/alloc/string/trait.ToString.html" title="trait alloc::string::ToString">ToString</a> for T<div class="where">where
T: <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/fmt/trait.Display.html" title="trait core::fmt::Display">Display</a> + ?<a class="trait" href="https://doc.rust-lang.org/1.80.0/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>,</div></h3></section></summary><div class="impl-items"><details class="toggle method-toggle" open><summary><section id="method.to_string" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/alloc/string.rs.html#2558">source</a><a href="#method.to_string" class="anchor">§</a><h4 class="code-header">default fn <a href="https://doc.rust-lang.org/1.80.0/alloc/string/trait.ToString.html#tymethod.to_string" class="fn">to_string</a>(&amp;self) -&gt; <a class="struct" href="https://doc.rust-lang.org/1.80.0/alloc/string/struct.String.html" title="struct alloc::string::String">String</a></h4></section></summary><div class='docblock'>Converts the given value to a <code>String</code>. <a href="https://doc.rust-lang.org/1.80.0/alloc/string/trait.ToString.html#tymethod.to_string">Read more</a></div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-TryFrom%3CU%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/convert/mod.rs.html#805-807">source</a><a href="#impl-TryFrom%3CU%3E-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T, U&gt; <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;U&gt; for T<div class="where">where
U: <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.Into.html" title="trait core::convert::Into">Into</a>&lt;T&gt;,</div></h3></section></summary><div class="impl-items"><details class="toggle" open><summary><section id="associatedtype.Error-2" class="associatedtype trait-impl"><a href="#associatedtype.Error-2" class="anchor">§</a><h4 class="code-header">type <a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html#associatedtype.Error" class="associatedtype">Error</a> = <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/convert/enum.Infallible.html" title="enum core::convert::Infallible">Infallible</a></h4></section></summary><div class='docblock'>The type returned in the event of a conversion error.</div></details><details class="toggle method-toggle" open><summary><section id="method.try_from-2" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/convert/mod.rs.html#812">source</a><a href="#method.try_from-2" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html#tymethod.try_from" class="fn">try_from</a>(value: U) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;T, &lt;T as <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;U&gt;&gt;::<a class="associatedtype" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a>&gt;</h4></section></summary><div class='docblock'>Performs the conversion.</div></details></div></details><details class="toggle implementors-toggle"><summary><section id="impl-TryInto%3CU%3E-for-T" class="impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/convert/mod.rs.html#790-792">source</a><a href="#impl-TryInto%3CU%3E-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T, U&gt; <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryInto.html" title="trait core::convert::TryInto">TryInto</a>&lt;U&gt; for T<div class="where">where
U: <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;T&gt;,</div></h3></section></summary><div class="impl-items"><details class="toggle" open><summary><section id="associatedtype.Error-3" class="associatedtype trait-impl"><a href="#associatedtype.Error-3" class="anchor">§</a><h4 class="code-header">type <a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryInto.html#associatedtype.Error" class="associatedtype">Error</a> = &lt;U as <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;T&gt;&gt;::<a class="associatedtype" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a></h4></section></summary><div class='docblock'>The type returned in the event of a conversion error.</div></details><details class="toggle method-toggle" open><summary><section id="method.try_into" class="method trait-impl"><a class="src rightside" href="https://doc.rust-lang.org/1.80.0/src/core/convert/mod.rs.html#797">source</a><a href="#method.try_into" class="anchor">§</a><h4 class="code-header">fn <a href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryInto.html#tymethod.try_into" class="fn">try_into</a>(self) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.80.0/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;U, &lt;U as <a class="trait" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html" title="trait core::convert::TryFrom">TryFrom</a>&lt;T&gt;&gt;::<a class="associatedtype" href="https://doc.rust-lang.org/1.80.0/core/convert/trait.TryFrom.html#associatedtype.Error" title="type core::convert::TryFrom::Error">Error</a>&gt;</h4></section></summary><div class='docblock'>Performs the conversion.</div></details></div></details></div><script type="text/json" id="notable-traits-data">{"CaptureMatches<'r, 'h>":"<h3>Notable traits for <code><a class=\"struct\" href=\"struct.CaptureMatches.html\" title=\"struct regex::CaptureMatches\">CaptureMatches</a>&lt;'r, 'h&gt;</code></h3><pre><code><div class=\"where\">impl&lt;'r, 'h&gt; <a class=\"trait\" href=\"https://doc.rust-lang.org/1.80.0/core/iter/traits/iterator/trait.Iterator.html\" title=\"trait core::iter::traits::iterator::Iterator\">Iterator</a> for <a class=\"struct\" href=\"struct.CaptureMatches.html\" title=\"struct regex::CaptureMatches\">CaptureMatches</a>&lt;'r, 'h&gt;</div><div class=\"where\"> type <a href=\"https://doc.rust-lang.org/1.80.0/core/iter/traits/iterator/trait.Iterator.html#associatedtype.Item\" class=\"associatedtype\">Item</a> = <a class=\"struct\" href=\"struct.Captures.html\" title=\"struct regex::Captures\">Captures</a>&lt;'h&gt;;</div>","CaptureNames<'_>":"<h3>Notable traits for <code><a class=\"struct\" href=\"struct.CaptureNames.html\" title=\"struct regex::CaptureNames\">CaptureNames</a>&lt;'r&gt;</code></h3><pre><code><div class=\"where\">impl&lt;'r&gt; 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