<?php
include_once $_SERVER['DOCUMENT_ROOT'] . '/include/shared-manual.inc';
$TOC = array();
$TOC_DEPRECATED = array();
$PARENTS = array();
include_once dirname(__FILE__) ."/toc/class.ds-set.inc";
$setup = array (
'home' =>
array (
0 => 'index.php',
1 => 'PHP Manual',
),
'head' =>
array (
0 => 'UTF-8',
1 => 'zh',
),
'this' =>
array (
0 => 'ds-set.reduce.php',
1 => 'Ds\\Set::reduce',
2 => 'Reduces the set to a single value using a callback function',
),
'up' =>
array (
0 => 'class.ds-set.php',
1 => 'Ds\\Set',
),
'prev' =>
array (
0 => 'ds-set.merge.php',
1 => 'Ds\\Set::merge',
),
'next' =>
array (
0 => 'ds-set.remove.php',
1 => 'Ds\\Set::remove',
),
'alternatives' =>
array (
),
'source' =>
array (
'lang' => 'en',
'path' => 'reference/ds/ds/set/reduce.xml',
),
'history' =>
array (
),
);
$setup["toc"] = $TOC;
$setup["toc_deprecated"] = $TOC_DEPRECATED;
$setup["parents"] = $PARENTS;
manual_setup($setup);
contributors($setup);
?>
<div id="ds-set.reduce" class="refentry">
<div class="refnamediv">
<h1 class="refname">Ds\Set::reduce</h1>
<p class="verinfo">(PECL ds >= 1.0.0)</p><p class="refpurpose"><span class="refname">Ds\Set::reduce</span> — <span class="dc-title">Reduces the set to a single value using a callback function</span></p>
</div>
<div class="refsect1 description" id="refsect1-ds-set.reduce-description">
<h3 class="title">说明</h3>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="methodname"><strong>Ds\Set::reduce</strong></span>(<span class="methodparam"><span class="type"><a href="language.types.callable.php" class="type callable">callable</a></span> <code class="parameter">$callback</code></span>, <span class="methodparam"><span class="type"><a href="language.types.mixed.php" class="type mixed">mixed</a></span> <code class="parameter">$initial</code><span class="initializer"> = ?</span></span>): <span class="type"><a href="language.types.mixed.php" class="type mixed">mixed</a></span></div>
<p class="para rdfs-comment">
Reduces the set to a single value using a callback function.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-ds-set.reduce-parameters">
<h3 class="title">参数</h3>
<dl>
<dt><code class="parameter">callback</code></dt>
<dd>
<div class="methodsynopsis dc-description"><span class="methodname"><span class="replaceable">callback</span></span>(<span class="methodparam"><span class="type"><a href="language.types.mixed.php" class="type mixed">mixed</a></span> <code class="parameter">$carry</code></span>, <span class="methodparam"><span class="type"><a href="language.types.mixed.php" class="type mixed">mixed</a></span> <code class="parameter">$value</code></span>): <span class="type"><a href="language.types.mixed.php" class="type mixed">mixed</a></span></div>
<dl>
<dt><code class="parameter">carry</code></dt>
<dd>
<p class="para">
The return value of the previous callback, or <code class="parameter">initial</code> if
it's the first iteration.
</p>
</dd>
<dt><code class="parameter">value</code></dt>
<dd>
<p class="para">
The value of the current iteration.
</p>
</dd>
</dl>
</dd>
<dt><code class="parameter">initial</code></dt>
<dd>
<p class="para">
The initial value of the carry value. Can be <strong><code><a href="reserved.constants.php#constant.null">null</a></code></strong>.
</p>
</dd>
</dl>
</div>
<div class="refsect1 returnvalues" id="refsect1-ds-set.reduce-returnvalues">
<h3 class="title">返回值</h3>
<p class="para">
The return value of the final callback.
</p>
</div>
<div class="refsect1 examples" id="refsect1-ds-set.reduce-examples">
<h3 class="title">示例</h3>
<div class="example" id="example-4412">
<p><strong>示例 #1 <span class="function"><strong>Ds\Set::reduce()</strong></span> with initial value example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$set </span><span style="color: #007700">= new </span><span style="color: #0000BB">\Ds\Set</span><span style="color: #007700">([</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">]);<br /><br /></span><span style="color: #0000BB">$callback </span><span style="color: #007700">= function(</span><span style="color: #0000BB">$carry</span><span style="color: #007700">, </span><span style="color: #0000BB">$value</span><span style="color: #007700">) {<br /> return </span><span style="color: #0000BB">$carry </span><span style="color: #007700">* </span><span style="color: #0000BB">$value</span><span style="color: #007700">;<br />};<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$set</span><span style="color: #007700">-></span><span style="color: #0000BB">reduce</span><span style="color: #007700">(</span><span style="color: #0000BB">$callback</span><span style="color: #007700">, </span><span style="color: #0000BB">5</span><span style="color: #007700">));<br /><br /></span><span style="color: #FF8000">// Iterations:<br />//<br />// $carry = $initial = 5<br />//<br />// $carry = $carry * 1 = 5<br />// $carry = $carry * 2 = 10<br />// $carry = $carry * 3 = 30<br /></span><span style="color: #0000BB">?></span></span></code></div>
</div>
<div class="example-contents"><p>以上示例的输出类似于：</p></div>
<div class="example-contents screen">
<div class="examplescode"><pre class="examplescode">int(30)</pre>
</div>
</div>
</div>
<div class="example" id="example-4413">
<p><strong>示例 #2 <span class="function"><strong>Ds\Set::reduce()</strong></span> without an initial value example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$set </span><span style="color: #007700">= new </span><span style="color: #0000BB">\Ds\Set</span><span style="color: #007700">([</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">]);<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$set</span><span style="color: #007700">-></span><span style="color: #0000BB">reduce</span><span style="color: #007700">(function(</span><span style="color: #0000BB">$carry</span><span style="color: #007700">, </span><span style="color: #0000BB">$value</span><span style="color: #007700">) {<br /> return </span><span style="color: #0000BB">$carry </span><span style="color: #007700">+ </span><span style="color: #0000BB">$value </span><span style="color: #007700">+ </span><span style="color: #0000BB">5</span><span style="color: #007700">;<br />}));<br /><br /></span><span style="color: #FF8000">// Iterations:<br />//<br />// $carry = $initial = null<br />//<br />// $carry = $carry + 1 + 5 = 6<br />// $carry = $carry + 2 + 5 = 13<br />// $carry = $carry + 3 + 5 = 21<br /></span><span style="color: #0000BB">?></span></span></code></div>
</div>
<div class="example-contents"><p>以上示例的输出类似于：</p></div>
<div class="example-contents screen">
<div class="examplescode"><pre class="examplescode">int(21)</pre>
</div>
</div>
</div>
</div>
</div><?php manual_footer($setup); ?>