function.array-filter.html
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<!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>Filtert Elemente eines Arrays mittels einer Callback-Funktion</title>
</head>
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</div><hr /><div id="function.array-filter" class="refentry">
<div class="refnamediv">
<h1 class="refname">array_filter</h1>
<p class="verinfo">(PHP 4 >= 4.0.6, PHP 5)</p><p class="refpurpose"><span class="refname">array_filter</span> — <span class="dc-title">Filtert Elemente eines Arrays mittels einer Callback-Funktion</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.array-filter-description">
<h3 class="title">Beschreibung</h3>
<div class="methodsynopsis dc-description">
<span class="type">array</span> <span class="methodname"><strong>array_filter</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>
] )</div>
<p class="para rdfs-comment">
Iteriert über jeden Wert im Array <code class="parameter">array</code>
und übergibt diesen der Callbackfunktion <code class="parameter">callback</code>.
Gibt die Funktion <code class="parameter">callback</code> true zurück, so
wird der aktuelle Wert von <code class="parameter">array</code> in das
Ergebnis-Array geschrieben. Die Schlüssel des Arrays bleiben erhalten.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.array-filter-parameters">
<h3 class="title">Parameter-Liste</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">array</code></dt>
<dd>
<p class="para">
Das Array, über das iteriert werden soll
</p>
</dd>
<dt>
<code class="parameter">callback</code></dt>
<dd>
<p class="para">
Die zu verwendende Callbackfunktion
</p>
<p class="para">
Falls die Funktion <code class="parameter">callback</code> nicht angegeben wurde,
werden alle Einträge aus <code class="parameter">array</code> entfernt,
die <strong><code>FALSE</code></strong> sind. Schauen Sie sich <a href="language.types.boolean.html#language.types.boolean.casting" class="link">Konvertierung in Booleans</a>
für mehr Informationen hierzu an.
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.array-filter-returnvalues">
<h3 class="title">Rückgabewerte</h3>
<p class="para">
Gibt das gefilterte Array zurück.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.array-filter-examples">
<h3 class="title">Beispiele</h3>
<p class="para">
<div class="example" id="example-4904">
<p><strong>Beispiel #1 <span class="function"><strong>array_filter()</strong></span>-Beispiel</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">ungerade</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">)<br />{<br /> </span><span style="color: #FF8000">// Gibt zurück, ob der Eingabewert ungerade ist<br /> </span><span style="color: #007700">return(</span><span style="color: #0000BB">$var </span><span style="color: #007700">& </span><span style="color: #0000BB">1</span><span style="color: #007700">);<br />}<br /><br />function </span><span style="color: #0000BB">gerade</span><span style="color: #007700">(</span><span style="color: #0000BB">$var</span><span style="color: #007700">)<br />{<br /> </span><span style="color: #FF8000">// Gibt zurück, ob der Eingabewert gerade ist<br /> </span><span style="color: #007700">return(!(</span><span style="color: #0000BB">$var </span><span style="color: #007700">& </span><span style="color: #0000BB">1</span><span style="color: #007700">));<br />}<br /><br /></span><span style="color: #0000BB">$array1 </span><span style="color: #007700">= array(</span><span style="color: #DD0000">"a"</span><span style="color: #007700">=></span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #DD0000">"b"</span><span style="color: #007700">=></span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #DD0000">"c"</span><span style="color: #007700">=></span><span style="color: #0000BB">3</span><span style="color: #007700">, </span><span style="color: #DD0000">"d"</span><span style="color: #007700">=></span><span style="color: #0000BB">4</span><span style="color: #007700">, </span><span style="color: #DD0000">"e"</span><span style="color: #007700">=></span><span style="color: #0000BB">5</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$array2 </span><span style="color: #007700">= array(</span><span style="color: #0000BB">6</span><span style="color: #007700">, </span><span style="color: #0000BB">7</span><span style="color: #007700">, </span><span style="color: #0000BB">8</span><span style="color: #007700">, </span><span style="color: #0000BB">9</span><span style="color: #007700">, </span><span style="color: #0000BB">10</span><span style="color: #007700">, </span><span style="color: #0000BB">11</span><span style="color: #007700">, </span><span style="color: #0000BB">12</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #DD0000">"Ungerade :\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">array_filter</span><span style="color: #007700">(</span><span style="color: #0000BB">$array1</span><span style="color: #007700">, </span><span style="color: #DD0000">"ungerade"</span><span style="color: #007700">));<br />echo </span><span style="color: #DD0000">"Gerade:\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">array_filter</span><span style="color: #007700">(</span><span style="color: #0000BB">$array2</span><span style="color: #007700">, </span><span style="color: #DD0000">"gerade"</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>Das oben gezeigte Beispiel erzeugt folgende
Ausgabe:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Ungerade :
Array
(
[a] => 1
[c] => 3
[e] => 5
)
Gerade:
Array
(
[0] => 6
[2] => 8
[4] => 10
[6] => 12
)
</pre></div>
</div>
</div>
<div class="example" id="example-4905">
<p><strong>Beispiel #2 <span class="function"><strong>array_filter()</strong></span> ohne
<code class="parameter">callback</code></strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />$entry </span><span style="color: #007700">= array(<br /> </span><span style="color: #0000BB">0 </span><span style="color: #007700">=> </span><span style="color: #DD0000">'foo'</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">1 </span><span style="color: #007700">=> </span><span style="color: #0000BB">false</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">2 </span><span style="color: #007700">=> -</span><span style="color: #0000BB">1</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">3 </span><span style="color: #007700">=> </span><span style="color: #0000BB">null</span><span style="color: #007700">,<br /> </span><span style="color: #0000BB">4 </span><span style="color: #007700">=> </span><span style="color: #DD0000">''<br /> </span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">print_r</span><span style="color: #007700">(</span><span style="color: #0000BB">array_filter</span><span style="color: #007700">(</span><span style="color: #0000BB">$entry</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>Das oben gezeigte Beispiel erzeugt folgende
Ausgabe:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
Array
(
[0] => foo
[2] => -1
)
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.array-filter-notes">
<h3 class="title">Anmerkungen</h3>
<div class="caution"><strong class="caution">Achtung</strong>
<p class="para">
Wird das Array durch die Callbackfunktion verändert (z.B. hinzufügen
oder löschen von Elementen oder ein unset-Aufruf), so ist das
Verhalten dieser Funktion undefiniert.
</p>
</div>
</div>
<div class="refsect1 seealso" id="refsect1-function.array-filter-seealso">
<h3 class="title">Siehe auch</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.array-map.html" class="function" rel="rdfs-seeAlso">array_map()</a> - Wendet eine Callback-Funktion auf die Elemente von Arrays an</span></li>
<li class="member"><span class="function"><a href="function.array-reduce.html" class="function" rel="rdfs-seeAlso">array_reduce()</a> - Iterative Reduktion eines Arrays zu einem Wert mittels einer
Callbackfunktion</span></li>
<li class="member"><span class="function"><a href="function.array-walk.html" class="function" rel="rdfs-seeAlso">array_walk()</a> - Wendet eine Benutzerfunktion auf jedem Element eines Arrays an</span></li>
</ul>
</p>
</div>
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