如何通过 PHP array_filter() 函数灵活筛选数组中的特定元素？

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() 函数介绍与灵活筛选应用</span></span><span>

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

<span class="hljs-comment">/**
 * 在 PHP 中，array_filter() 是一个非常强大的内置函数，
 * 它能够通过回调函数对数组中的元素进行筛选，
 * 返回满足条件的子数组，从而帮助开发者灵活处理数据。
 * 本文将详细介绍 array_filter() 的用法及一些实用的筛选技巧。
 */</span>

</span><span><span class="hljs-comment">// 1. 基础用法：筛选出非空元素</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">/*
结果：
Array
(
    [1] =&gt; 1
    [2] =&gt; 2
    [6] =&gt; hello
)
*/</span>
</span><span><span class="hljs-comment">// 说明：没有提供回调函数时，array_filter() 默认去除所有“等价于 false”的值。</span></span><span>

</span><span><span class="hljs-comment">// 2. 自定义回调函数筛选特定条件的元素</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">/*
结果：
Array
(
    [1] =&gt; 2
    [3] =&gt; 4
    [5] =&gt; 6
)
*/</span>
</span><span><span class="hljs-comment">// 说明：回调函数返回 true 的元素会被保留，false 的会被过滤掉。</span></span><span>

</span><span><span class="hljs-comment">// 3. 使用键名过滤</span></span><span>
</span><span><span class="hljs-variable">$assoc</span></span><span> = [
    </span><span><span class="hljs-string">'apple'</span></span><span> =&gt; </span><span><span class="hljs-number">3</span></span><span>,
    </span><span><span class="hljs-string">'banana'</span></span><span> =&gt; </span><span><span class="hljs-number">5</span></span><span>,
    </span><span><span class="hljs-string">'cherry'</span></span><span> =&gt; </span><span><span class="hljs-number">1</span></span><span>,
    </span><span><span class="hljs-string">'date'</span></span><span> =&gt; </span><span><span class="hljs-number">7</span></span><span>,
];
</span><span><span class="hljs-comment">// 只保留键名长度大于5的元素</span></span><span>
</span><span><span class="hljs-variable">$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">/*
结果：
Array
(
    [banana] =&gt; 5
    [cherry] =&gt; 1
)
*/</span>

</span><span><span class="hljs-comment">// 4. 多层数组筛选示例</span></span><span>
</span><span><span class="hljs-variable">$users</span></span><span> = [
    [</span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Alice'</span></span><span>, </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">23</span></span><span>, </span><span><span class="hljs-string">'active'</span></span><span> =&gt; </span><span><span class="hljs-literal">true</span></span><span>],
    [</span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Bob'</span></span><span>, </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">30</span></span><span>, </span><span><span class="hljs-string">'active'</span></span><span> =&gt; </span><span><span class="hljs-literal">false</span></span><span>],
    [</span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Charlie'</span></span><span>, </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">27</span></span><span>, </span><span><span class="hljs-string">'active'</span></span><span> =&gt; </span><span><span class="hljs-literal">true</span></span><span>],
];
</span><span><span class="hljs-comment">// 筛选出年龄大于25且活跃的用户</span></span><span>
</span><span><span class="hljs-variable">$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">/*
结果：
Array
(
    [2] =&gt; Array
        (
            [name] =&gt; Charlie
            [age] =&gt; 27
            [active] =&gt; 1
        )
)
*/</span>

</span><span><span class="hljs-comment">// 5. 注意事项及性能建议</span></span><span>
</span><span><span class="hljs-comment">// - array_filter 不会重新索引数组，保留原始键名。</span></span><span>
</span><span><span class="hljs-comment">// - 如果需要连续索引，可配合 array_values 使用。</span></span><span>
</span><span><span class="hljs-comment">// - 在处理大数组时，尽量简化回调函数逻辑，避免性能瓶颈。</span></span><span>

</span><span><span class="hljs-comment">// 总结：</span></span><span>
</span><span><span class="hljs-comment">// array_filter() 是 PHP 中筛选数组元素的利器，通过灵活定义回调函数，</span></span><span>
</span><span><span class="hljs-comment">// 可实现各种复杂的筛选需求，提升代码简洁度和可读性。</span></span><span>

</span><span><span class="hljs-meta">?&gt;</span></span><span>
</span></span>
相关标签:
array_filter
array