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determine which values to include</title>
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<h1 class="refname">Ds\Set::filter</h1>
<p class="verinfo">(PECL ds >= 1.0.0)</p><p class="refpurpose"><span class="refname">Ds\Set::filter</span> — <span class="dc-title">
Creates a new set 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-set.filter-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type"><span class="type Ds\Set">Ds\Set</span></span> <span class="methodname"><strong>Ds\Set::filter</strong></span>
([ <span class="methodparam"><span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <code class="parameter">$callback</code></span>
] )</div>
<p class="para rdfs-comment">
Creates a new set using a <span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> to
determine which values to include.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-ds-set.filter-parameters">
<h3 class="title">Parameters</h3>
<dl>
<dt>
<code class="parameter">callback</code></dt>
<dd>
<p class="para">
<div class="methodsynopsis dc-description">
<span class="type">bool</span>
<span class="methodname"><span class="replaceable">callback</span></span>
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$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-set.filter-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
A new set 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-set.filter-examples">
<h3 class="title">Examples</h3>
<div class="example" id="example-5307">
<p><strong>Example #1 <span class="function"><strong>Ds\Set::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 />$set </span><span style="color: #007700">= new \</span><span style="color: #0000BB">Ds</span><span style="color: #007700">\</span><span style="color: #0000BB">Set</span><span style="color: #007700">([</span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #0000BB">4</span><span style="color: #007700">, </span><span style="color: #0000BB">5</span><span style="color: #007700">]);<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$set</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\Set)#3 (2) {
[0]=>
int(2)
[1]=>
int(4)
}
</pre></div>
</div>
</div>
<div class="example" id="example-5308">
<p><strong>Example #2 <span class="function"><strong>Ds\Set::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 />$set </span><span style="color: #007700">= new \</span><span style="color: #0000BB">Ds</span><span style="color: #007700">\</span><span style="color: #0000BB">Set</span><span style="color: #007700">([</span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #DD0000">'a'</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">, </span><span style="color: #0000BB">false</span><span style="color: #007700">]);<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$set</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\Set)#2 (3) {
[0]=>
int(1)
[1]=>
string(1) "a"
[2]=>
bool(true)
}
</pre></div>
</div>
</div>
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