usort

實例

使用用戶自定義的比較函數對數組$a 中的元素進行排序：

 <span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token keyword">function</span> <span class="token function-definition function">my_sort</span> <span class="token punctuation">(</span> <span class="token variable">$a</span> <span class="token punctuation">,</span> <span class="token variable">$b</span> <span class="token punctuation">)</span>
<span class="token punctuation">{</span>
<span class="token keyword">if</span> <span class="token punctuation">(</span> <span class="token variable">$a</span> <span class="token operator">==</span> <span class="token variable">$b</span> <span class="token punctuation">)</span> <span class="token keyword">return</span> <span class="token number">0</span> <span class="token punctuation">;</span>
<span class="token keyword">return</span> <span class="token punctuation">(</span> <span class="token variable">$a</span> <span class="token operator"><</span> <span class="token variable">$b</span> <span class="token punctuation">)</span> <span class="token operator">?</span> <span class="token operator">-</span> <span class="token number">1</span> <span class="token punctuation">:</span> <span class="token number">1</span> <span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token variable">$a</span> <span class="token operator">=</span> <span class="token keyword">array</span> <span class="token punctuation">(</span> <span class="token number">4</span> <span class="token punctuation">,</span> <span class="token number">2</span> <span class="token punctuation">,</span> <span class="token number">8</span> <span class="token punctuation">,</span> <span class="token number">6</span> <span class="token punctuation">)</span> <span class="token punctuation">;</span>
<span class="token function"></span></span><mark><span class="token function">usort</span> <span class="token punctuation">(</span> <span class="token variable">$a</span> <span class="token punctuation">,</span> <span class="token string double-quoted-string">"my_sort"</span> <span class="token punctuation">)</span></mark><span class="token punctuation"></span> <span class="token punctuation">;</span>
<span class="token delimiter important">?></span>

親自試一試