多維數組中，如何用uksort函數進行準確的鍵排序處理？

gitbox 2025-06-23

[多維數組中，如何用uksort函數進行準確的鍵排序處理？ ]

在PHP中，數組是非常強大且靈活的數據結構。多維數組是其中一個常見的應用場景，常用於存儲複雜的數據。然而，很多時候我們會遇到需要根據鍵進行排序的需求。 PHP 提供了多種排序數組的函數，其中uksort()是一個可以自定義排序規則的函數，常用於根據鍵對數組進行排序。本文將重點介紹如何在多維數組中使用uksort()函數進行準確的鍵排序。

1. 什麼是uksort函數？

uksort()是PHP 中的一個函數，它通過用戶自定義的比較函數對數組的鍵進行排序。該函數的基本語法如下：

 <span><span><span class="hljs-title function_ invoke__">uksort</span></span><span>(</span><span><span class="hljs-keyword">array</span></span><span> &amp;</span><span><span class="hljs-variable">$array</span></span><span>, </span><span><span class="hljs-keyword">callable</span></span><span> </span><span><span class="hljs-variable">$cmp_function</span></span><span>): </span><span><span class="hljs-keyword">bool</span></span><span>
</span></span>

array ：需要排序的數組（按鍵排序）。
cmp_function ：用於比較數組鍵的回調函數。回調函數必須返回一個整數，來決定兩個鍵的排序順序。

2. 多維數組的結構與排序需求

在處理多維數組時，通常數組中的元素本身也是數組。比如，假設我們有一個記錄學生信息的多維數組，每個學生的信息包括名字、年齡和分數等：

 <span><span><span class="hljs-variable">$students</span></span><span> = [
    </span><span><span class="hljs-string">'student1'</span></span><span> =&gt; [</span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Tom'</span></span><span>, </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">20</span></span><span>, </span><span><span class="hljs-string">'score'</span></span><span> =&gt; </span><span><span class="hljs-number">88</span></span><span>],
    </span><span><span class="hljs-string">'student2'</span></span><span> =&gt; [</span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Jerry'</span></span><span>, </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">21</span></span><span>, </span><span><span class="hljs-string">'score'</span></span><span> =&gt; </span><span><span class="hljs-number">92</span></span><span>],
    </span><span><span class="hljs-string">'student3'</span></span><span> =&gt; [</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">22</span></span><span>, </span><span><span class="hljs-string">'score'</span></span><span> =&gt; </span><span><span class="hljs-number">85</span></span><span>],
    </span><span><span class="hljs-string">'student4'</span></span><span> =&gt; [</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">20</span></span><span>, </span><span><span class="hljs-string">'score'</span></span><span> =&gt; </span><span><span class="hljs-number">95</span></span><span>]
];
</span></span>

在這種多維數組中，我們的目標可能是根據某個鍵（如學生的名字、年齡、或分數）進行排序。

3. 使用uksort排序多維數組

要在多維數組中根據鍵進行排序，我們首先需要理解如何通過uksort()自定義排序規則。通常來說，我們是根據每個數組的某一項值來排序。

假設我們想根據每個學生的年齡進行排序。因為uksort()只處理外層數組的鍵，而不會直接操作內部的鍵，所以我們需要通過一個比較函數來訪問每個學生的年齡並根據它進行排序。

以下是使用uksort()函數根據學生年齡排序的示例：

 <span><span><span class="hljs-variable">$students</span></span><span> = [
    </span><span><span class="hljs-string">'student1'</span></span><span> =&gt; [</span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Tom'</span></span><span>, </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">20</span></span><span>, </span><span><span class="hljs-string">'score'</span></span><span> =&gt; </span><span><span class="hljs-number">88</span></span><span>],
    </span><span><span class="hljs-string">'student2'</span></span><span> =&gt; [</span><span><span class="hljs-string">'name'</span></span><span> =&gt; </span><span><span class="hljs-string">'Jerry'</span></span><span>, </span><span><span class="hljs-string">'age'</span></span><span> =&gt; </span><span><span class="hljs-number">21</span></span><span>, </span><span><span class="hljs-string">'score'</span></span><span> =&gt; </span><span><span class="hljs-number">92</span></span><span>],
    </span><span><span class="hljs-string">'student3'</span></span><span> =&gt; [</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">22</span></span><span>, </span><span><span class="hljs-string">'score'</span></span><span> =&gt; </span><span><span class="hljs-number">85</span></span><span>],
    </span><span><span class="hljs-string">'student4'</span></span><span> =&gt; [</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">20</span></span><span>, </span><span><span class="hljs-string">'score'</span></span><span> =&gt; </span><span><span class="hljs-number">95</span></span><span>]
];

</span><span><span class="hljs-comment">// 自定義比較函數</span></span><span>
</span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">compare_age</span></span><span>(</span><span><span class="hljs-params"><span class="hljs-variable">$a</span></span></span><span>, </span><span><span class="hljs-variable">$b</span></span><span>) {
    </span><span><span class="hljs-keyword">global</span></span><span> </span><span><span class="hljs-variable">$students</span></span><span>;
    </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable">$students</span></span><span>[</span><span><span class="hljs-variable">$a</span></span><span>][</span><span><span class="hljs-string">'age'</span></span><span>] - </span><span><span class="hljs-variable">$students</span></span><span>[</span><span><span class="hljs-variable">$b</span></span><span>][</span><span><span class="hljs-string">'age'</span></span><span>];
}

</span><span><span class="hljs-comment">// 使用uksort對數組按學生年齡排序</span></span><span>
</span><span><span class="hljs-title function_ invoke__">uksort</span></span><span>(</span><span><span class="hljs-variable">$students</span></span><span>, </span><span><span class="hljs-string">'compare_age'</span></span><span>);

</span><span><span class="hljs-comment">// 輸出排序後的結果</span></span><span>
</span><span><span class="hljs-title function_ invoke__">print_r</span></span><span>(</span><span><span class="hljs-variable">$students</span></span><span>);
</span></span>

解釋：

自定義比較函數compare_age ：它接收兩個參數（分別是兩個數組的鍵）。通過這兩個鍵，我們從$students數組中訪問學生的年齡，並將其進行比較，返回一個整數來決定排序順序。
uksort()調用：我們將compare_age函數作為參數傳遞給uksort() ，這將根據年齡對學生數組的鍵進行排序。

4. 按其他鍵排序

假設我們想根據學生的分數進行排序，方法與年齡排序類似，只需要修改比較函數中的訪問值即可。

 <span><span><span class="hljs-comment">// 自定義比較函數（按分數排序）</span></span><span>
</span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">compare_score</span></span><span>(</span><span><span class="hljs-params"><span class="hljs-variable">$a</span></span></span><span>, </span><span><span class="hljs-variable">$b</span></span><span>) {
    </span><span><span class="hljs-keyword">global</span></span><span> </span><span><span class="hljs-variable">$students</span></span><span>;
    </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable">$students</span></span><span>[</span><span><span class="hljs-variable">$a</span></span><span>][</span><span><span class="hljs-string">'score'</span></span><span>] - </span><span><span class="hljs-variable">$students</span></span><span>[</span><span><span class="hljs-variable">$b</span></span><span>][</span><span><span class="hljs-string">'score'</span></span><span>];
}

</span><span><span class="hljs-comment">// 使用uksort按分數對數組進行排序</span></span><span>
</span><span><span class="hljs-title function_ invoke__">uksort</span></span><span>(</span><span><span class="hljs-variable">$students</span></span><span>, </span><span><span class="hljs-string">'compare_score'</span></span><span>);

</span><span><span class="hljs-comment">// 輸出排序後的結果</span></span><span>
</span><span><span class="hljs-title function_ invoke__">print_r</span></span><span>(</span><span><span class="hljs-variable">$students</span></span><span>);
</span></span>

5. 複雜排序場景

在某些複雜的排序場景中，我們可能需要根據多個條件進行排序，例如，首先按年齡排序，如果年齡相同，則按分數排序。我們可以在比較函數中同時比較多個字段來實現這一點：

 <span><span><span class="hljs-comment">// 自定義比較函數（按年齡和分數排序）</span></span><span>
</span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">compare_age_and_score</span></span><span>(</span><span><span class="hljs-params"><span class="hljs-variable">$a</span></span></span><span>, </span><span><span class="hljs-variable">$b</span></span><span>) {
    </span><span><span class="hljs-keyword">global</span></span><span> </span><span><span class="hljs-variable">$students</span></span><span>;
    </span><span><span class="hljs-comment">// 比較年齡</span></span><span>
    </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$students</span></span><span>[</span><span><span class="hljs-variable">$a</span></span><span>][</span><span><span class="hljs-string">'age'</span></span><span>] == </span><span><span class="hljs-variable">$students</span></span><span>[</span><span><span class="hljs-variable">$b</span></span><span>][</span><span><span class="hljs-string">'age'</span></span><span>]) {
        </span><span><span class="hljs-comment">// 如果年齡相同，按分數排序</span></span><span>
        </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable">$students</span></span><span>[</span><span><span class="hljs-variable">$a</span></span><span>][</span><span><span class="hljs-string">'score'</span></span><span>] - </span><span><span class="hljs-variable">$students</span></span><span>[</span><span><span class="hljs-variable">$b</span></span><span>][</span><span><span class="hljs-string">'score'</span></span><span>];
    }
    </span><span><span class="hljs-comment">// 否則按年齡排序</span></span><span>
    </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable">$students</span></span><span>[</span><span><span class="hljs-variable">$a</span></span><span>][</span><span><span class="hljs-string">'age'</span></span><span>] - </span><span><span class="hljs-variable">$students</span></span><span>[</span><span><span class="hljs-variable">$b</span></span><span>][</span><span><span class="hljs-string">'age'</span></span><span>];
}

</span><span><span class="hljs-comment">// 使用uksort進行複雜排序</span></span><span>
</span><span><span class="hljs-title function_ invoke__">uksort</span></span><span>(</span><span><span class="hljs-variable">$students</span></span><span>, </span><span><span class="hljs-string">'compare_age_and_score'</span></span><span>);

</span><span><span class="hljs-comment">// 輸出排序後的結果</span></span><span>
</span><span><span class="hljs-title function_ invoke__">print_r</span></span><span>(</span><span><span class="hljs-variable">$students</span></span><span>);
</span></span>

6. 總結

uksort()是一個強大的工具，可以幫助我們根據自定義的規則對數組的鍵進行排序。對於多維數組，通常我們需要通過外層數組的鍵來訪問內部元素的值，然後根據這些值進行排序。無論是單一條件排序還是複雜的多條件排序， uksort()都能提供靈活的支持。

希望本文的講解能幫助你理解如何使用uksort()在多維數組中進行鍵排序，並根據你的需求進行靈活的調整和使用。

uksort