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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Fetch a key from an array</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.in-array.html">in_array</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.krsort.html">krsort</a></div> <div class="up"><a href="ref.array.html">Array Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.key" class="refentry"> <div class="refnamediv"> <h1 class="refname">key</h1> <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">key</span> — <span class="dc-title">Fetch a key from an array</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <span class="methodname"><b><b>key</b></b></span> ( <span class="methodparam"><span class="type">array</span> <tt class="parameter reference">&$array</tt></span> )</div> <p class="para rdfs-comment"> <b>key()</b> returns the index element of the current array position. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">array</tt></i></span> <dd> <p class="para"> The array. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns the index. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 <b>key()</b> example</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$array </span><span style="color: #007700">= array(<br /> </span><span style="color: #DD0000">'fruit1' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'apple'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'fruit2' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'orange'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'fruit3' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'grape'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'fruit4' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'apple'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'fruit5' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'apple'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// this cycle echoes all associative array<br />// key where value equals "apple"<br /></span><span style="color: #007700">while (</span><span style="color: #0000BB">$fruit_name </span><span style="color: #007700">= </span><span style="color: #0000BB">current</span><span style="color: #007700">(</span><span style="color: #0000BB">$array</span><span style="color: #007700">)) {<br /> if (</span><span style="color: #0000BB">$fruit_name </span><span style="color: #007700">== </span><span style="color: #DD0000">'apple'</span><span style="color: #007700">) {<br /> echo </span><span style="color: #0000BB">key</span><span style="color: #007700">(</span><span style="color: #0000BB">$array</span><span style="color: #007700">).</span><span style="color: #DD0000">'<br />'</span><span style="color: #007700">;<br /> }<br /> </span><span style="color: #0000BB">next</span><span style="color: #007700">(</span><span style="color: #0000BB">$array</span><span style="color: #007700">);<br />}<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> <div class="example-contents"><p>The above example will output:</p></div> <div class="example-contents"><pre><div class="cdata"><pre>fruit1<br />fruit4<br />fruit5<br /></pre></div> </pre></div> </div> </p> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="function.current.html" class="function" rel="rdfs-seeAlso">current()</a></li> <li class="member"><a href="function.next.html" class="function" rel="rdfs-seeAlso">next()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.in-array.html">in_array</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.krsort.html">krsort</a></div> <div class="up"><a href="ref.array.html">Array Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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