function.array-rand.html
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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>Pick one or more random entries out of 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.array-push.html">array_push</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.array-reduce.html">array_reduce</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.array-rand" class="refentry"> <div class="refnamediv"> <h1 class="refname">array_rand</h1> <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">array_rand</span> — <span class="dc-title">Pick one or more random entries out of 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>array_rand</b></b></span> ( <span class="methodparam"><span class="type">array</span> <tt class="parameter">$input</tt></span> [, <span class="methodparam"><span class="type">int</span> <tt class="parameter">$num_req</tt></span> ] )</div> <p class="para rdfs-comment"> <b>array_rand()</b> is rather useful when you want to pick one or more random entries out of an array. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">input</tt></i></span> <dd> <p class="para"> The input array. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">num_req</tt></i></span> <dd> <p class="para"> Specifies how many entries you want to pick - if not specified, defaults to 1. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> If you are picking only one entry, <b>array_rand()</b> returns the key for a random entry. Otherwise, it returns an array of keys for the random entries. This is done so that you can pick random keys as well as values out of the array. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 <b>array_rand()</b> example</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />srand</span><span style="color: #007700">((float) </span><span style="color: #0000BB">microtime</span><span style="color: #007700">() * </span><span style="color: #0000BB">10000000</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$input </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"Neo"</span><span style="color: #007700">, </span><span style="color: #DD0000">"Morpheus"</span><span style="color: #007700">, </span><span style="color: #DD0000">"Trinity"</span><span style="color: #007700">, </span><span style="color: #DD0000">"Cypher"</span><span style="color: #007700">, </span><span style="color: #DD0000">"Tank"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$rand_keys </span><span style="color: #007700">= </span><span style="color: #0000BB">array_rand</span><span style="color: #007700">(</span><span style="color: #0000BB">$input</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">$input</span><span style="color: #007700">[</span><span style="color: #0000BB">$rand_keys</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">]] . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">$input</span><span style="color: #007700">[</span><span style="color: #0000BB">$rand_keys</span><span style="color: #007700">[</span><span style="color: #0000BB">1</span><span style="color: #007700">]] . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 notes"> <h3 class="title">Notes</h3> <blockquote><p><b class="note">Note</b>: <span class="simpara">As of PHP 4.2.0, there is no need to seed the random number generator with <a href="function.srand.html" class="function">srand()</a> or <a href="function.mt-srand.html" class="function">mt_srand()</a> as this is now done automatically.</span></p></blockquote> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="function.shuffle.html" class="function" rel="rdfs-seeAlso">shuffle()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.array-push.html">array_push</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.array-reduce.html">array_reduce</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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