<!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>Creates a new sequence using a callable to determine which values to include</title> </head> <body><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="ds-sequence.contains.html">Ds\Sequence::contains</a></div> <div class="next" style="text-align: right; float: right;"><a href="ds-sequence.find.html">Ds\Sequence::find</a></div> <div class="up"><a href="class.ds-sequence.html">Sequence</a></div> <div class="home"><a href="index.html">PHP Manual</a></div> </div><hr /><div id="ds-sequence.filter" class="refentry"> <div class="refnamediv"> <h1 class="refname">Ds\Sequence::filter</h1> <p class="verinfo">(PECL ds >= 1.0.0)</p><p class="refpurpose"><span class="refname">Ds\Sequence::filter</span> — <span class="dc-title"> Creates a new sequence using a <span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> to determine which values to include </span></p> </div> <div class="refsect1 description" id="refsect1-ds-sequence.filter-description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="modifier">abstract</span> <span class="modifier">public</span> <span class="type"><span class="type Ds\Sequence">Ds\Sequence</span></span> <span class="methodname"><strong>Ds\Sequence::filter</strong></span> ([ <span class="methodparam"><span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <code class="parameter">$callback</code></span> ] )</div> <p class="para rdfs-comment"> Creates a new sequence using a <span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> to determine which values to include. </p> </div> <div class="refsect1 parameters" id="refsect1-ds-sequence.filter-parameters"> <h3 class="title">Parameters</h3> <dl> <dt> <code class="parameter">callback</code></dt> <dd> <p class="para"> <div class="methodsynopsis dc-description"> <span class="type">bool</span> <span class="methodname"><span class="replaceable">callback</span></span> ( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$value</code></span> )</div> </p> <p class="para"> Optional <span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> which returns <strong><code>TRUE</code></strong> if the value should be included, <strong><code>FALSE</code></strong> otherwise. </p> <p class="para"> If a callback is not provided, only values which are <strong><code>TRUE</code></strong> (see <a href="language.types.boolean.html#language.types.boolean.casting" class="link">converting to boolean</a>) will be included. </p> </dd> </dl> </div> <div class="refsect1 returnvalues" id="refsect1-ds-sequence.filter-returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> A new sequence containing all the values for which either the <code class="parameter">callback</code> returned <strong><code>TRUE</code></strong>, or all values that convert to <strong><code>TRUE</code></strong> if a <code class="parameter">callback</code> was not provided. </p> </div> <div class="refsect1 examples" id="refsect1-ds-sequence.filter-examples"> <h3 class="title">Examples</h3> <div class="example" id="example-5138"> <p><strong>Example #1 <span class="function"><strong>Ds\Sequence::filter()</strong></span> example using callback function</strong></p> <div class="example-contents"> <div class="phpcode"><code><span style="color: #000000"> <span style="color: #0000BB"><?php<br />$sequence </span><span style="color: #007700">= new \</span><span style="color: #0000BB">Ds</span><span style="color: #007700">\</span><span style="color: #0000BB">Vector</span><span style="color: #007700">([</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #0000BB">4</span><span style="color: #007700">, </span><span style="color: #0000BB">5</span><span style="color: #007700">]);<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$sequence</span><span style="color: #007700">-></span><span style="color: #0000BB">filter</span><span style="color: #007700">(function(</span><span style="color: #0000BB">$value</span><span style="color: #007700">) {<br /> return </span><span style="color: #0000BB">$value </span><span style="color: #007700">% </span><span style="color: #0000BB">2 </span><span style="color: #007700">== </span><span style="color: #0000BB">0</span><span style="color: #007700">;<br />}));<br /></span><span style="color: #0000BB">?></span> </span> </code></div> </div> <div class="example-contents"><p>The above example will output something similar to:</p></div> <div class="example-contents screen"> <div class="cdata"><pre> object(Ds\Vector)#3 (2) { [0]=> int(2) [1]=> int(4) } </pre></div> </div> </div> <div class="example" id="example-5139"> <p><strong>Example #2 <span class="function"><strong>Ds\Sequence::filter()</strong></span> example without a callback function</strong></p> <div class="example-contents"> <div class="phpcode"><code><span style="color: #000000"> <span style="color: #0000BB"><?php<br />$sequence </span><span style="color: #007700">= new \</span><span style="color: #0000BB">Ds</span><span style="color: #007700">\</span><span style="color: #0000BB">Vector</span><span style="color: #007700">([</span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #DD0000">'a'</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">, </span><span style="color: #0000BB">false</span><span style="color: #007700">]);<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$sequence</span><span style="color: #007700">-></span><span style="color: #0000BB">filter</span><span style="color: #007700">());<br /></span><span style="color: #0000BB">?></span> </span> </code></div> </div> <div class="example-contents"><p>The above example will output something similar to:</p></div> <div class="example-contents screen"> <div class="cdata"><pre> object(Ds\Vector)#2 (3) { [0]=> int(1) [1]=> string(1) "a" [2]=> bool(true) } </pre></div> </div> </div> </div> </div><hr /><div class="manualnavbar" style="text-align: center;"> <div class="prev" style="text-align: 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