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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>Assign variables as if they were 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.ksort.html">ksort</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.natcasesort.html">natcasesort</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.list" class="refentry"> <div class="refnamediv"> <h1 class="refname">list</h1> <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">list</span> — <span class="dc-title">Assign variables as if they were an array</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type"><span class="type void">void</span></span> <span class="methodname"><b><b>list</b></b></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">$varname</tt></span> [, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <tt class="parameter">$...</tt></span> ] )</div> <p class="para rdfs-comment"> Like <a href="function.array.html" class="function">array()</a>, this is not really a function, but a language construct. <b>list()</b> is used to assign a list of variables in one operation. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">varname</tt></i></span> <dd> <p class="para"> A variable. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> No value is returned. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 <b>list()</b> examples</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /><br />$info </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'coffee'</span><span style="color: #007700">, </span><span style="color: #DD0000">'brown'</span><span style="color: #007700">, </span><span style="color: #DD0000">'caffeine'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Listing all the variables<br /></span><span style="color: #007700">list(</span><span style="color: #0000BB">$drink</span><span style="color: #007700">, </span><span style="color: #0000BB">$color</span><span style="color: #007700">, </span><span style="color: #0000BB">$power</span><span style="color: #007700">) = </span><span style="color: #0000BB">$info</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"$drink is $color and $power makes it special.\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// Listing some of them<br /></span><span style="color: #007700">list(</span><span style="color: #0000BB">$drink</span><span style="color: #007700">, , </span><span style="color: #0000BB">$power</span><span style="color: #007700">) = </span><span style="color: #0000BB">$info</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"$drink has $power.\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// Or let's skip to only the third one<br /></span><span style="color: #007700">list( , , </span><span style="color: #0000BB">$power</span><span style="color: #007700">) = </span><span style="color: #0000BB">$info</span><span style="color: #007700">;<br />echo </span><span style="color: #DD0000">"I need $power!\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// list() doesn't work with strings<br /></span><span style="color: #007700">list(</span><span style="color: #0000BB">$bar</span><span style="color: #007700">) = </span><span style="color: #DD0000">"abcde"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$bar</span><span style="color: #007700">); </span><span style="color: #FF8000">// NULL<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> <p class="para"> <div class="example"> <p><b>Example #2 An example use of <b>list()</b></b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><table><br /> <tr><br /> <th>Employee name</th><br /> <th>Salary</th><br /> </tr><br /><br /><span style="color: #0000BB"><?php<br /><br />$result </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_query</span><span style="color: #007700">(</span><span style="color: #DD0000">"SELECT id, name, salary FROM employees"</span><span style="color: #007700">, </span><span style="color: #0000BB">$conn</span><span style="color: #007700">);<br />while (list(</span><span style="color: #0000BB">$id</span><span style="color: #007700">, </span><span style="color: #0000BB">$name</span><span style="color: #007700">, </span><span style="color: #0000BB">$salary</span><span style="color: #007700">) = </span><span style="color: #0000BB">mysql_fetch_row</span><span style="color: #007700">(</span><span style="color: #0000BB">$result</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">" <tr>\n" </span><span style="color: #007700">.<br /> </span><span style="color: #DD0000">" <td><a href=\"info.php?id=$id\">$name</a></td>\n" </span><span style="color: #007700">.<br /> </span><span style="color: #DD0000">" <td>$salary</td>\n" </span><span style="color: #007700">.<br /> </span><span style="color: #DD0000">" </tr>\n"</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">?><br /></span><br /></table></span></code></div> </div> </div> </p> <p class="para"> <div class="example"> <p><b>Example #3 Using nested <b>list()</b></b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /><br /></span><span style="color: #007700">list(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, list(</span><span style="color: #0000BB">$b</span><span style="color: #007700">, </span><span style="color: #0000BB">$c</span><span style="color: #007700">)) = array(</span><span style="color: #0000BB">1</span><span style="color: #007700">, array(</span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #0000BB">$b</span><span style="color: #007700">, </span><span style="color: #0000BB">$c</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span></span></code></div> </div> <div class="example-contents"><pre><div class="cdata"><pre>int(1)int(2)int(3)</pre></div> </pre></div> </div> </p> <p class="para"> <div class="example"> <p><b>Example #4 Using <b>list()</b> with array indices</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /><br />$info </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'coffee'</span><span style="color: #007700">, </span><span style="color: #DD0000">'brown'</span><span style="color: #007700">, </span><span style="color: #DD0000">'caffeine'</span><span style="color: #007700">);<br /><br />list(</span><span style="color: #0000BB">$a</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">], </span><span style="color: #0000BB">$a</span><span style="color: #007700">[</span><span style="color: #0000BB">1</span><span style="color: #007700">], </span><span style="color: #0000BB">$a</span><span style="color: #007700">[</span><span style="color: #0000BB">2</span><span style="color: #007700">]) = </span><span style="color: #0000BB">$info</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span></span></code></div> </div> <div class="example-contents"><p> Gives the following output (note the order of the elements compared in which order they were written in the <b>list()</b> syntax): </p></div> <div class="example-contents"><pre><div class="cdata"><pre>array(3) { [2]=> string(8) "caffeine" [1]=> string(5) "brown" [0]=> string(6) "coffee"}</pre></div> </pre></div> </div> </p> </div> <div class="refsect1 notes"> <h3 class="title">Notes</h3> <div class="warning"><b class="warning">Warning</b> <p class="para"> <b>list()</b> assigns the values starting with the right-most parameter. If you are using plain variables, you don't have to worry about this. But if you are using arrays with indices you usually expect the order of the indices in the array the same you wrote in the <b>list()</b> from left to right; which it isn't. It's assigned in the reverse order. </p> </div> <blockquote><p><b class="note">Note</b>: <b>list()</b> only works on numerical arrays and assumes the numerical indices start at 0. <br /> </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.each.html" class="function" rel="rdfs-seeAlso">each()</a></li> <li class="member"><a href="function.array.html" class="function" rel="rdfs-seeAlso">array()</a></li> <li class="member"><a href="function.extract.html" class="function" rel="rdfs-seeAlso">extract()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.ksort.html">ksort</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.natcasesort.html">natcasesort</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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