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120 lines
6.1 KiB
HTML
120 lines
6.1 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="content-type" content="text/html; charset=UTF-8">
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<title>从关联数组中取得键名</title>
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</head>
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<body class="docs"><div id="layout">
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<div id="layout-content"><div id="function.key" class="refentry">
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<div class="refnamediv">
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<h1 class="refname">key</h1>
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<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">key</span> — <span class="dc-title">从关联数组中取得键名</span></p>
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</div>
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<div class="refsect1 description" id="refsect1-function.key-description">
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<h3 class="title">说明</h3>
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<div class="methodsynopsis dc-description">
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<span class="methodname"><strong>key</strong></span>
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( <span class="methodparam"><span class="type">array</span> <code class="parameter">$array</code></span>
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) : <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span></div>
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<p class="para rdfs-comment">
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<span class="function"><strong>key()</strong></span> 返回数组中当前单元的键名。
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</p>
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</div>
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<div class="refsect1 parameters" id="refsect1-function.key-parameters">
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<h3 class="title">参数</h3>
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<p class="para">
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<dl>
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<dt>
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<code class="parameter">array</code></dt>
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<dd>
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<p class="para">
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该数组。
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</p>
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</dd>
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</dl>
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</p>
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</div>
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<div class="refsect1 returnvalues" id="refsect1-function.key-returnvalues">
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<h3 class="title">返回值</h3>
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<p class="para">
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<span class="function"><strong>key()</strong></span> 函数返回数组中内部指针指向的当前单元的键名。
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但它不会移动指针。如果内部指针超过了元素列表尾部，或者数组是空的，<span class="function"><strong>key()</strong></span> 会返回 <strong><code>NULL</code></strong>。
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</p>
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</div>
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<div class="refsect1 changelog" id="refsect1-function.key-changelog">
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<h3 class="title">更新日志</h3>
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<p class="para">
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<table class="doctable informaltable">
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<thead>
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<tr>
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<th>版本</th>
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<th>说明</th>
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</tr>
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</thead>
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<tbody class="tbody">
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<tr>
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<td>7.0.0</td>
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<td>
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<code class="parameter">array</code> 现在总是会传值。
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在此之前，它会尽可能传引用，否则就传值。
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</td>
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</tr>
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</tbody>
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</table>
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</p>
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</div>
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<div class="refsect1 examples" id="refsect1-function.key-examples">
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<h3 class="title">范例</h3>
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<p class="para">
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<div class="example" id="example-6100">
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<p><strong>Example #1 <span class="function"><strong>key()</strong></span> 例子</strong></p>
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<div class="example-contents">
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<div class="phpcode"><pre><span style="color: #000000">
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<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>
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</span>
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</pre></div>
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</div>
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<div class="example-contents"><p>以上例程会输出：</p></div>
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<div class="example-contents screen">
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<div class="cdata"><pre>
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fruit1<br />
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fruit4<br />
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fruit5<br />
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</pre></div>
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</div>
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</div>
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</p>
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</div>
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<div class="refsect1 seealso" id="refsect1-function.key-seealso">
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<h3 class="title">参见</h3>
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<p class="para">
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<ul class="simplelist">
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<li class="member"><span class="function"><a href="current.html" class="function" rel="rdfs-seeAlso">current()</a> - 返回数组中的当前单元</span></li>
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<li class="member"><span class="function"><a href="next.html" class="function" rel="rdfs-seeAlso">next()</a> - 将数组中的内部指针向前移动一位</span></li>
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<li class="member"><a href="control_structures.foreach.html" class="link">foreach</a></li>
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</ul>
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</p>
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</div>
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</div></div></div></body></html> |