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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>Apply a user function to every member 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-walk-recursive.html">array_walk_recursive</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.array.html">array</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-walk" class="refentry"> <div class="refnamediv"> <h1 class="refname">array_walk</h1> <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">array_walk</span> — <span class="dc-title">Apply a user function to every member of an array</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">bool</span> <span class="methodname"><b><b>array_walk</b></b></span> ( <span class="methodparam"><span class="type">array</span> <tt class="parameter reference">&$array</tt></span> , <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.callback" class="type callback">callback</a></span> <tt class="parameter">$funcname</tt></span> [, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <tt class="parameter">$userdata</tt></span> ] )</div> <p class="simpara"> Applies the user-defined function <i><tt class="parameter">funcname</tt></i> to each element of the <i><tt class="parameter">array</tt></i> array. </p> <p class="para"> <b>array_walk()</b> is not affected by the internal array pointer of <i><tt class="parameter">array</tt></i>. <b>array_walk()</b> will walk through the entire array regardless of pointer 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 input array. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">funcname</tt></i></span> <dd> <p class="para"> Typically, <i><tt class="parameter">funcname</tt></i> takes on two parameters. The <i><tt class="parameter">array</tt></i> parameter's value being the first, and the key/index second. </p> <blockquote><p><b class="note">Note</b>: If <i><tt class="parameter">funcname</tt></i> needs to be working with the actual values of the array, specify the first parameter of <i><tt class="parameter">funcname</tt></i> as a <a href="language.references.html" class="link">reference</a>. Then, any changes made to those elements will be made in the original array itself. <br /> </p></blockquote> <p class="para"> Users may not change the <i><tt class="parameter">array</tt></i> itself from the callback function. e.g. Add/delete elements, unset elements, etc. If the array that <b>array_walk()</b> is applied to is changed, the behavior of this function is undefined, and unpredictable. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">userdata</tt></i></span> <dd> <p class="para"> If the optional <i><tt class="parameter">userdata</tt></i> parameter is supplied, it will be passed as the third parameter to the callback <i><tt class="parameter">funcname</tt></i>. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns <b><tt>TRUE</tt></b> on success or <b><tt>FALSE</tt></b> on failure. </p> </div> <div class="refsect1 errors"> <h3 class="title">Errors/Exceptions</h3> <p class="para"> If function <i><tt class="parameter">funcname</tt></i> requires more parameters than given to it, an error of level <a href="errorfunc.constants.html" class="link"> E_WARNING</a> will be generated each time <b>array_walk()</b> calls <i><tt class="parameter">funcname</tt></i>. These warnings may be suppressed by prepending the PHP error operator <a href="language.operators.errorcontrol.html" class="link">@</a> to the <b>array_walk()</b> call, or by using <a href="function.error-reporting.html" class="function">error_reporting()</a>. </p> </div> <div class="refsect1 changelog"> <h3 class="title">ChangeLog</h3> <p class="para"> <table class="informaltable"> <colgroup> <thead valign="middle"> <tr valign="middle"> <th colspan="1">Version</th> <th colspan="1">Description</th> </tr> </thead> <tbody valign="middle" class="tbody"> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">4.0.0</td> <td colspan="1" rowspan="1" align="left"> Passing the key and <i><tt class="parameter">userdata</tt></i> to <i><tt class="parameter">funcname</tt></i> was added. </td> </tr> </tbody> </colgroup> </table> </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 <b>array_walk()</b> example</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$fruits </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"d" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"lemon"</span><span style="color: #007700">, </span><span style="color: #DD0000">"a" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"orange"</span><span style="color: #007700">, </span><span style="color: #DD0000">"b" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"banana"</span><span style="color: #007700">, </span><span style="color: #DD0000">"c" </span><span style="color: #007700">=> </span><span style="color: #DD0000">"apple"</span><span style="color: #007700">);<br /><br />function </span><span style="color: #0000BB">test_alter</span><span style="color: #007700">(&</span><span style="color: #0000BB">$item1</span><span style="color: #007700">, </span><span style="color: #0000BB">$key</span><span style="color: #007700">, </span><span style="color: #0000BB">$prefix</span><span style="color: #007700">)<br />{<br /> </span><span style="color: #0000BB">$item1 </span><span style="color: #007700">= </span><span style="color: #DD0000">"$prefix: $item1"</span><span style="color: #007700">;<br />}<br /><br />function </span><span style="color: #0000BB">test_print</span><span style="color: #007700">(</span><span style="color: #0000BB">$item2</span><span style="color: #007700">, </span><span style="color: #0000BB">$key</span><span style="color: #007700">)<br />{<br /> echo </span><span style="color: #DD0000">"$key. $item2<br />\n"</span><span style="color: #007700">;<br />}<br /><br />echo </span><span style="color: #DD0000">"Before ...:\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">array_walk</span><span style="color: #007700">(</span><span style="color: #0000BB">$fruits</span><span style="color: #007700">, </span><span style="color: #DD0000">'test_print'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">array_walk</span><span style="color: #007700">(</span><span style="color: #0000BB">$fruits</span><span style="color: #007700">, </span><span style="color: #DD0000">'test_alter'</span><span style="color: #007700">, </span><span style="color: #DD0000">'fruit'</span><span style="color: #007700">);<br />echo </span><span style="color: #DD0000">"... and after:\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">array_walk</span><span style="color: #007700">(</span><span style="color: #0000BB">$fruits</span><span style="color: #007700">, </span><span style="color: #DD0000">'test_print'</span><span style="color: #007700">);<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>Before ...:d. lemona. orangeb. bananac. apple... and after:d. fruit: lemona. fruit: orangeb. fruit: bananac. fruit: apple</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.array-walk-recursive.html" class="function" rel="rdfs-seeAlso">array_walk_recursive()</a></li> <li class="member"><a href="function.create-function.html" class="function" rel="rdfs-seeAlso">create_function()</a></li> <li class="member"><a href="function.list.html" class="function" rel="rdfs-seeAlso">list()</a></li> <li class="member"><a href="function.each.html" class="function" rel="rdfs-seeAlso">each()</a></li> <li class="member"><a href="function.call-user-func-array.html" class="function" rel="rdfs-seeAlso">call_user_func_array()</a></li> <li class="member"><a href="function.array-map.html" class="function" rel="rdfs-seeAlso">array_map()</a></li> <li class="member">information about the <a href="language.pseudo-types.html#language.types.callback" class="link">callback</a> type</li> <li class="member"><a href="control-structures.foreach.html" class="link">foreach</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-walk-recursive.html">array_walk_recursive</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.array.html">array</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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