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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>Rewind the internal array pointer</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.pos.html">pos</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.range.html">range</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.prev" class="refentry"> <div class="refnamediv"> <h1 class="refname">prev</h1> <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">prev</span> — <span class="dc-title">Rewind the internal array pointer</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>prev</b></b></span> ( <span class="methodparam"><span class="type">array</span> <tt class="parameter reference">&$array</tt></span> )</div> <p class="para rdfs-comment"> Rewind the internal array pointer. </p> <p class="para"> <b>prev()</b> behaves just like <a href="function.next.html" class="function">next()</a>, except it rewinds the internal array pointer one place instead of advancing it. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">array</tt></i></span> <dd> <p class="para"> The input array. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns the array value in the previous place that's pointed to by the internal array pointer, or <b><tt>FALSE</tt></b> if there are no more elements. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 Example use of <b>prev()</b> and friends</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$transport </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'foot'</span><span style="color: #007700">, </span><span style="color: #DD0000">'bike'</span><span style="color: #007700">, </span><span style="color: #DD0000">'car'</span><span style="color: #007700">, </span><span style="color: #DD0000">'plane'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$mode </span><span style="color: #007700">= </span><span style="color: #0000BB">current</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">); </span><span style="color: #FF8000">// $mode = 'foot';<br /></span><span style="color: #0000BB">$mode </span><span style="color: #007700">= </span><span style="color: #0000BB">next</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">); </span><span style="color: #FF8000">// $mode = 'bike';<br /></span><span style="color: #0000BB">$mode </span><span style="color: #007700">= </span><span style="color: #0000BB">next</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">); </span><span style="color: #FF8000">// $mode = 'car';<br /></span><span style="color: #0000BB">$mode </span><span style="color: #007700">= </span><span style="color: #0000BB">prev</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">); </span><span style="color: #FF8000">// $mode = 'bike';<br /></span><span style="color: #0000BB">$mode </span><span style="color: #007700">= </span><span style="color: #0000BB">end</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">); </span><span style="color: #FF8000">// $mode = 'plane';<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 notes"> <h3 class="title">Notes</h3> <div class="warning"><b class="warning">Warning</b><p class="simpara">This function mayreturn Boolean <b><tt>FALSE</tt></b>, but may also return a non-Boolean value whichevaluates to <b><tt>FALSE</tt></b>, such as <i>0</i> or"". Please read the section on <a href="language.types.boolean.html" class="link">Booleans</a> for moreinformation. Use <a href="language.operators.comparison.html" class="link">the ===operator</a> for testing the return value of thisfunction.</p></div> <blockquote><p><b class="note">Note</b>: <span class="simpara"> You won't be able to distinguish the beginning of an array from a <a href="language.types.boolean.html" class="type boolean">boolean</a> <b><tt>FALSE</tt></b> element. To properly traverse an array which may contain <b><tt>FALSE</tt></b> elements, see the <a href="function.each.html" class="function">each()</a> function. </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.current.html" class="function" rel="rdfs-seeAlso">current()</a></li> <li class="member"><a href="function.end.html" class="function" rel="rdfs-seeAlso">end()</a></li> <li class="member"><a href="function.next.html" class="function" rel="rdfs-seeAlso">next()</a></li> <li class="member"><a href="function.reset.html" class="function" rel="rdfs-seeAlso">reset()</a></li> <li class="member"><a href="function.each.html" class="function" rel="rdfs-seeAlso">each()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.pos.html">pos</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.range.html">range</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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