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Wie kann ich spezifische Elemente in einem Array flexibel durch die Funktion PHP Array_filter () filtern?

M66 2025-07-29 
<span><span><span class="hljs-meta">&lt;?php</span></span><span>
</span><span><span class="hljs-comment">// -------------------------------------------------------------</span></span><span>

</span><span><span class="hljs-comment">// PHP array_filter() Funktioneinführung und flexible Filteranwendungen</span></span><span>

</span><span><span class="hljs-comment">// -------------------------------------------------------------</span></span><span>

<span class="hljs-comment">/**
 * existieren PHP Mitte，array_filter() Es ist eine sehr leistungsstarke integrierte Funktion，
 * 它能够通过回调函数对数组MitteElemente进行筛选，
 * Gibt eine Subtarray zurück, die den Kriterien erfüllt，Dies hilft Entwicklern, Daten flexibel zu verarbeiten。
 * Dieser Artikel wird ausführlich vorgestellt array_filter() Verwendung und einige praktische Screening -Techniken。
 */</span>

</span><span><span class="hljs-comment">// 1. Grundnutzung：Filtern Sie nicht leere Elemente heraus</span></span><span>
</span><span><span class="hljs-variable">$input</span></span><span> = [</span><span><span class="hljs-number">0</span></span><span>, </span><span><span class="hljs-number">1</span></span><span>, </span><span><span class="hljs-number">2</span></span><span>, </span><span><span class="hljs-string">''</span></span><span>, </span><span><span class="hljs-literal">null</span></span><span>, </span><span><span class="hljs-literal">false</span></span><span>, </span><span><span class="hljs-string">'hello'</span></span><span>, </span><span><span class="hljs-string">'0'</span></span><span>];
</span><span><span class="hljs-variable">$filtered</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_filter</span></span><span>(</span><span><span class="hljs-variable">$input</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">print_r</span></span><span>(</span><span><span class="hljs-variable">$filtered</span></span><span>);
<span class="hljs-comment">/*
Ergebnis：
Array
(
    [1] =&gt; 1
    [2] =&gt; 2
    [6] =&gt; hello
)
*/</span>
</span><span><span class="hljs-comment">// veranschaulichen：Wenn keine Rückruffunktion bereitgestellt wird，array_filter() Entfernen Sie alle standardmäßig“Äquivalent zu false”Wert von。</span></span><span>

</span><span><span class="hljs-comment">// 2. Benutzerdefinierte Rückruffunktionen, um Elemente bestimmter Bedingungen zu filtern</span></span><span>
</span><span><span class="hljs-variable">$numbers</span></span><span> = [</span><span><span class="hljs-number">1</span></span><span>, </span><span><span class="hljs-number">2</span></span><span>, </span><span><span class="hljs-number">3</span></span><span>, </span><span><span class="hljs-number">4</span></span><span>, </span><span><span class="hljs-number">5</span></span><span>, </span><span><span class="hljs-number">6</span></span><span>];
</span><span><span class="hljs-variable">$evenNumbers</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_filter</span></span><span>(</span><span><span class="hljs-variable">$numbers</span></span><span>, function(</span><span><span class="hljs-variable">$num</span></span><span>) {
    </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable">$num</span></span><span> % </span><span><span class="hljs-number">2</span></span><span> === </span><span><span class="hljs-number">0</span></span><span>;
});
</span><span><span class="hljs-title function_ invoke__">print_r</span></span><span>(</span><span><span class="hljs-variable">$evenNumbers</span></span><span>);
<span class="hljs-comment">/*
Ergebnis：
Array
(
    [1] =&gt; 2
    [3] =&gt; 4
    [5] =&gt; 6
)
*/</span>
</span><span><span class="hljs-comment">// veranschaulichen：Rückruffunktion kehrt zurück true Die Elemente von，false Es wird herausgefiltert。</span></span><span>

</span><span><span class="hljs-comment">// 3. Verwenden Sie den Schlüsselnamenfilterung</span></span><span>
</span><span><span class="hljs-variable">$assoc</span></span><span> = [
    </span><span><span class="hljs-string">'apple'</span></span><span> =&gt; </span><span><span class="hljs-number">3</span></span><span>,
    </span><span><span class="hljs-string">'banana'</span></span><span> =&gt; </span><span><span class="hljs-number">5</span></span><span>,
    </span><span><span class="hljs-string">'cherry'</span></span><span> =&gt; </span><span><span class="hljs-number">1</span></span><span>,
    </span><span><span class="hljs-string">'date'</span></span><span> =&gt; </span><span><span class="hljs-number">7</span></span><span>,
];
</span><span><span class="hljs-comment">// Nur die Länge der Schlüsselnamen ist größer als5Elemente</span></span><span>
</span><span><span class="hljs-variable">$filteredByKey</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_filter</span></span><span>(</span><span><span class="hljs-variable">$assoc</span></span><span>, function(</span><span><span class="hljs-variable">$value</span></span><span>, </span><span><span class="hljs-variable">$key</span></span><span>) {
    </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-title function_ invoke__">strlen</span></span><span>(</span><span><span class="hljs-variable">$key</span></span><span>) &gt; </span><span><span class="hljs-number">5</span></span><span>;
}, ARRAY_FILTER_USE_BOTH);
</span><span><span class="hljs-title function_ invoke__">print_r</span></span><span>(</span><span><span class="hljs-variable">$filteredByKey</span></span><span>);
<span class="hljs-comment">/*
Ergebnis：
Array
(
    [banana] =&gt; 5
    [cherry] =&gt; 1
)
*/</span>

</span><span><span class="hljs-comment">// 4. Beispiel für mehrschichtige Array-Array-Beispiele</span></span><span>
</span><span><span class="hljs-variable">$users</span></span><span> = [
    [</span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Alice'</span></span><span>, </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">23</span></span><span>, </span><span><span class="hljs-string">'active'</span></span><span> =&gt; </span><span><span class="hljs-literal">true</span></span><span>],
    [</span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Bob'</span></span><span>, </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">30</span></span><span>, </span><span><span class="hljs-string">'active'</span></span><span> =&gt; </span><span><span class="hljs-literal">false</span></span><span>],
    [</span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Charlie'</span></span><span>, </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">27</span></span><span>, </span><span><span class="hljs-string">'active'</span></span><span> =&gt; </span><span><span class="hljs-literal">true</span></span><span>],
];
</span><span><span class="hljs-comment">// Filtern älter als25Aktive Benutzer</span></span><span>
</span><span><span class="hljs-variable">$activeAdults</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_filter</span></span><span>(</span><span><span class="hljs-variable">$users</span></span><span>, function(</span><span><span class="hljs-variable">$user</span></span><span>) {
    </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable">$user</span></span><span>[</span><span><span class="hljs-string">'age'</span></span><span>] &gt; </span><span><span class="hljs-number">25</span></span><span> &amp;&amp; </span><span><span class="hljs-variable">$user</span></span><span>[</span><span><span class="hljs-string">'active'</span></span><span>] === </span><span><span class="hljs-literal">true</span></span><span>;
});
</span><span><span class="hljs-title function_ invoke__">print_r</span></span><span>(</span><span><span class="hljs-variable">$activeAdults</span></span><span>);
<span class="hljs-comment">/*
Ergebnis：
Array
(
    [2] =&gt; Array
        (
            [name] =&gt; Charlie
            [age] =&gt; 27
            [active] =&gt; 1
        )
)
*/</span>

</span><span><span class="hljs-comment">// 5. Vorsichtsmaßnahmen und Leistungsvorschläge</span></span><span>
</span><span><span class="hljs-comment">// - array_filter Das Array wird nicht wieder integriert，Behalten Sie den ursprünglichen Schlüssellamen。</span></span><span>
</span><span><span class="hljs-comment">// - Wenn eine kontinuierliche Indexierung erforderlich ist，Kann kooperieren array_values verwenden。</span></span><span>
</span><span><span class="hljs-comment">// - existieren处理大数组时，Versuchen Sie, die Rückruffunktionslogik zu vereinfachen，Vermeiden Sie Leistungs Engpässe。</span></span><span>

</span><span><span class="hljs-comment">// Zusammenfassen：</span></span><span>
</span><span><span class="hljs-comment">// array_filter() Ja PHP Mitte筛选数组元素的利器，Flexible Definition von Rückruffunktionen，</span></span><span>
</span><span><span class="hljs-comment">// Eine Vielzahl komplexer Screening -Anforderungen kann erreicht werden，Verbessern Sie die Codes -Einfachheit und -lesbarkeit。</span></span><span>

</span><span><span class="hljs-meta">?&gt;</span></span><span>
</span></span>
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