uTools-Manuals/docs/php/current.html
2019-04-28 19:00:34 +08:00

104 lines
8.2 KiB
HTML

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>返回数组中的当前单元</title>
</head>
<body class="docs"><div id="layout">
<div id="layout-content"><div id="function.current" class="refentry">
<div class="refnamediv">
<h1 class="refname">current</h1>
<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">current</span> &mdash; <span class="dc-title">返回数组中的当前单元</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.current-description">
<h3 class="title">说明</h3>
<div class="methodsynopsis dc-description">
<span class="methodname"><strong>current</strong></span>
( <span class="methodparam"><span class="type">array</span> <code class="parameter reference">&$array</code></span>
) : <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span></div>
<p class="para rdfs-comment">
每个数组中都有一个内部的指针指向它“当前的”单元,初始指向插入到数组中的第一个单元。
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.current-parameters">
<h3 class="title">参数</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">array</code></dt>
<dd>
<p class="para">
这个数组。
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.current-returnvalues">
<h3 class="title">返回值</h3>
<p class="para">
<span class="function"><strong>current()</strong></span> 函数返回当前被内部指针指向的数组单元的值,并不移动指针。如果内部指针指向超出了单元列表的末端,<span class="function"><strong>current()</strong></span>
返回 <strong><code>FALSE</code></strong>
</p>
<div class="warning"><strong class="warning">Warning</strong><p class="simpara">此函数可能返回布尔值
<strong><code>FALSE</code></strong>,但也可能返回等同于 <strong><code>FALSE</code></strong> 的非布尔值。请阅读 <a href="language.types.boolean.html" class="link">布尔类型</a>章节以获取更多信息。应使用
<a href="language.operators.comparison.html" class="link">===
运算符</a>来测试此函数的返回值。</p></div>
</div>
<div class="refsect1 examples" id="refsect1-function.current-examples">
<h3 class="title">范例</h3>
<p class="para">
<div class="example" id="example-6092">
<p><strong>Example #1 使用 <span class="function"><strong>current()</strong></span> 系列函数的例子</strong></p>
<div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$transport&nbsp;</span><span style="color: #007700">=&nbsp;array(</span><span style="color: #DD0000">'foot'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'bike'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'car'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'plane'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$mode&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">current</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//&nbsp;$mode&nbsp;=&nbsp;'foot';<br /></span><span style="color: #0000BB">$mode&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">next</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">);&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;$mode&nbsp;=&nbsp;'bike';<br /></span><span style="color: #0000BB">$mode&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">current</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//&nbsp;$mode&nbsp;=&nbsp;'bike';<br /></span><span style="color: #0000BB">$mode&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">prev</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">);&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;$mode&nbsp;=&nbsp;'foot';<br /></span><span style="color: #0000BB">$mode&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">end</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;$mode&nbsp;=&nbsp;'plane';<br /></span><span style="color: #0000BB">$mode&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">current</span><span style="color: #007700">(</span><span style="color: #0000BB">$transport</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//&nbsp;$mode&nbsp;=&nbsp;'plane';<br /><br /></span><span style="color: #0000BB">$arr&nbsp;</span><span style="color: #007700">=&nbsp;array();<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">current</span><span style="color: #007700">(</span><span style="color: #0000BB">$arr</span><span style="color: #007700">));&nbsp;</span><span style="color: #FF8000">//&nbsp;bool(false)<br /><br /></span><span style="color: #0000BB">$arr&nbsp;</span><span style="color: #007700">=&nbsp;array(array());<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">current</span><span style="color: #007700">(</span><span style="color: #0000BB">$arr</span><span style="color: #007700">));&nbsp;</span><span style="color: #FF8000">//&nbsp;array(0)&nbsp;{&nbsp;}<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.current-notes">
<h3 class="title">注释</h3>
<blockquote class="note"><p><strong class="note">Note</strong>:
<span class="simpara">
如果数组包含 <span class="type"><a href="language.types.boolean.html" class="type boolean">boolean</a></span> <strong><code>FALSE</code></strong> 的单元则本函数在碰到这个单元时也返回
<strong><code>FALSE</code></strong>,使得不可能判断是否到了此数组列表的末端。
要正确遍历可能含有空单元的数组,用 <span class="function"><a href="each.html" class="function">each()</a></span> 函数。
</span>
</p></blockquote>
</div>
<div class="refsect1 seealso" id="refsect1-function.current-seealso">
<h3 class="title">参见</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="end.html" class="function" rel="rdfs-seeAlso">end()</a> - 将数组的内部指针指向最后一个单元</span></li>
<li class="member"><span class="function"><a href="key.html" class="function" rel="rdfs-seeAlso">key()</a> - 从关联数组中取得键名</span></li>
<li class="member"><span class="function"><a href="each.html" class="function" rel="rdfs-seeAlso">each()</a> - 返回数组中当前的键/值对并将数组指针向前移动一步</span></li>
<li class="member"><span class="function"><a href="prev.html" class="function" rel="rdfs-seeAlso">prev()</a> - 将数组的内部指针倒回一位</span></li>
<li class="member"><span class="function"><a href="reset.html" class="function" rel="rdfs-seeAlso">reset()</a> - 将数组的内部指针指向第一个单元</span></li>
<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>
</ul>
</p>
</div>
</div></div></div></body></html>