mirror of
https://github.com/fofolee/uTools-Manuals.git
synced 2025-06-18 05:26:57 +08:00
175 lines
9.5 KiB
HTML
175 lines
9.5 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>用回调函数迭代地将数组简化为单一的值</title>
|
|
</head>
|
|
<body class="docs"><div id="layout">
|
|
<div id="layout-content"><div id="function.array-reduce" class="refentry">
|
|
<div class="refnamediv">
|
|
<h1 class="refname">array_reduce</h1>
|
|
<p class="verinfo">(PHP 4 >= 4.0.5, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">array_reduce</span> — <span class="dc-title">用回调函数迭代地将数组简化为单一的值</span></p>
|
|
|
|
</div>
|
|
<div class="refsect1 description" id="refsect1-function.array-reduce-description">
|
|
<h3 class="title">说明</h3>
|
|
<div class="methodsynopsis dc-description">
|
|
<span class="methodname"><strong>array_reduce</strong></span>
|
|
( <span class="methodparam"><span class="type">array</span> <code class="parameter">$array</code></span>
|
|
, <span class="methodparam"><span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <code class="parameter">$callback</code></span>
|
|
[, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$initial</code><span class="initializer"> = <strong><code>NULL</code></strong></span></span>
|
|
] ) : <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span></div>
|
|
|
|
<p class="para rdfs-comment">
|
|
<span class="function"><strong>array_reduce()</strong></span> 将回调函数
|
|
<code class="parameter">callback</code> 迭代地作用到
|
|
<code class="parameter">array</code> 数组中的每一个单元中，从而将数组简化为单一的值。
|
|
</p>
|
|
</div>
|
|
|
|
<div class="refsect1 parameters" id="refsect1-function.array-reduce-parameters">
|
|
<h3 class="title">参数</h3>
|
|
<p class="para">
|
|
<dl>
|
|
|
|
|
|
<dt>
|
|
<code class="parameter">array</code></dt>
|
|
|
|
<dd>
|
|
|
|
<p class="para">
|
|
输入的 array。
|
|
</p>
|
|
</dd>
|
|
|
|
|
|
|
|
<dt>
|
|
<code class="parameter">callback</code></dt>
|
|
|
|
<dd>
|
|
|
|
<div class="methodsynopsis dc-description">
|
|
<span class="methodname"><span class="replaceable">callback</span></span>
|
|
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$carry</code></span>
|
|
, <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$item</code></span>
|
|
) : <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span></div>
|
|
|
|
<dl>
|
|
|
|
|
|
<dt>
|
|
<code class="parameter">carry</code></dt>
|
|
|
|
<dd>
|
|
|
|
<p class="para">
|
|
携带上次迭代里的值；
|
|
如果本次迭代是第一次，那么这个值是 <code class="parameter">initial</code>。
|
|
</p>
|
|
</dd>
|
|
|
|
|
|
|
|
<dt>
|
|
<code class="parameter">item</code></dt>
|
|
|
|
<dd>
|
|
|
|
<p class="para">
|
|
携带了本次迭代的值。
|
|
</p>
|
|
</dd>
|
|
|
|
|
|
</dl>
|
|
|
|
</dd>
|
|
|
|
|
|
|
|
<dt>
|
|
<code class="parameter">initial</code></dt>
|
|
|
|
<dd>
|
|
|
|
<p class="para">
|
|
如果指定了可选参数
|
|
<code class="parameter">initial</code>，该参数将在处理开始前使用，或者当处理结束，数组为空时的最后一个结果。
|
|
</p>
|
|
</dd>
|
|
|
|
|
|
</dl>
|
|
|
|
</p>
|
|
</div>
|
|
|
|
<div class="refsect1 returnvalues" id="refsect1-function.array-reduce-returnvalues">
|
|
<h3 class="title">返回值</h3>
|
|
<p class="para">
|
|
返回结果值。
|
|
</p>
|
|
<p class="para">
|
|
<code class="parameter">initial</code> 参数，<span class="function"><strong>array_reduce()</strong></span> 返回 <strong><code>NULL</code></strong>。
|
|
</p>
|
|
</div>
|
|
|
|
<div class="refsect1 changelog" id="refsect1-function.array-reduce-changelog">
|
|
<h3 class="title">更新日志</h3>
|
|
<p class="para">
|
|
<table class="doctable informaltable">
|
|
|
|
<thead>
|
|
<tr>
|
|
<th>版本</th>
|
|
<th>说明</th>
|
|
</tr>
|
|
|
|
</thead>
|
|
|
|
<tbody class="tbody">
|
|
<tr>
|
|
<td>5.3.0</td>
|
|
<td>
|
|
修改 <code class="parameter">initial</code> 类型，允许传入 <span class="type"><a href="language.pseudo_types.html#language.types.mixed" class="type mixed">mixed</a></span>，之前只能是 <span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>。
|
|
</td>
|
|
</tr>
|
|
|
|
</tbody>
|
|
|
|
</table>
|
|
|
|
</p>
|
|
</div>
|
|
|
|
<div class="refsect1 examples" id="refsect1-function.array-reduce-examples">
|
|
<h3 class="title">范例</h3>
|
|
<p class="para">
|
|
<div class="example" id="example-6059">
|
|
<p><strong>Example #1 <span class="function"><strong>array_reduce()</strong></span> 例子</strong></p>
|
|
<div class="example-contents">
|
|
<div class="phpcode"><pre><span style="color: #000000">
|
|
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">sum</span><span style="color: #007700">(</span><span style="color: #0000BB">$carry</span><span style="color: #007700">, </span><span style="color: #0000BB">$item</span><span style="color: #007700">)<br />{<br /> </span><span style="color: #0000BB">$carry </span><span style="color: #007700">+= </span><span style="color: #0000BB">$item</span><span style="color: #007700">;<br /> return </span><span style="color: #0000BB">$carry</span><span style="color: #007700">;<br />}<br /><br />function </span><span style="color: #0000BB">product</span><span style="color: #007700">(</span><span style="color: #0000BB">$carry</span><span style="color: #007700">, </span><span style="color: #0000BB">$item</span><span style="color: #007700">)<br />{<br /> </span><span style="color: #0000BB">$carry </span><span style="color: #007700">*= </span><span style="color: #0000BB">$item</span><span style="color: #007700">;<br /> return </span><span style="color: #0000BB">$carry</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">$a </span><span style="color: #007700">= array(</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #0000BB">4</span><span style="color: #007700">, </span><span style="color: #0000BB">5</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$x </span><span style="color: #007700">= array();<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">array_reduce</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #DD0000">"sum"</span><span style="color: #007700">)); </span><span style="color: #FF8000">// int(15)<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">array_reduce</span><span style="color: #007700">(</span><span style="color: #0000BB">$a</span><span style="color: #007700">, </span><span style="color: #DD0000">"product"</span><span style="color: #007700">, </span><span style="color: #0000BB">10</span><span style="color: #007700">)); </span><span style="color: #FF8000">// int(1200), because: 10*1*2*3*4*5<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">array_reduce</span><span style="color: #007700">(</span><span style="color: #0000BB">$x</span><span style="color: #007700">, </span><span style="color: #DD0000">"sum"</span><span style="color: #007700">, </span><span style="color: #DD0000">"No data to reduce"</span><span style="color: #007700">)); </span><span style="color: #FF8000">// string(17) "No data to reduce"<br /></span><span style="color: #0000BB">?></span>
|
|
</span>
|
|
</pre></div>
|
|
</div>
|
|
|
|
</div>
|
|
</p>
|
|
</div>
|
|
|
|
<div class="refsect1 seealso" id="refsect1-function.array-reduce-seealso">
|
|
<h3 class="title">参见</h3>
|
|
<p class="para">
|
|
<ul class="simplelist">
|
|
<li class="member"><span class="function"><a href="array_filter.html" class="function" rel="rdfs-seeAlso">array_filter()</a> - 用回调函数过滤数组中的单元</span></li>
|
|
<li class="member"><span class="function"><a href="array_map.html" class="function" rel="rdfs-seeAlso">array_map()</a> - 为数组的每个元素应用回调函数</span></li>
|
|
<li class="member"><span class="function"><a href="array_unique.html" class="function" rel="rdfs-seeAlso">array_unique()</a> - 移除数组中重复的值</span></li>
|
|
<li class="member"><span class="function"><a href="array_count_values.html" class="function" rel="rdfs-seeAlso">array_count_values()</a> - 统计数组中所有的值</span></li>
|
|
</ul>
|
|
</p>
|
|
</div>
|
|
|
|
</div></div></div></body></html> |