usort

例

ユーザー定義の比較関数を使用して、配列$ aの要素をソートします。

 <span class="token php language-php"><span class="token delimiter important"><？php</span>
<span class="token keyword">機能</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 number">0</span><span class="token keyword">を返します</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">-1</span> <span class="token punctuation">：</span> <span class="token number">1</span> <span class="token punctuation">;</span><span class="token number">​</span>
<span class="token punctuation">}</span>

<span class="token variable">$</span> <span class="token punctuation">a</span> <span class="token operator">=</span> <span class="token keyword">array</span> <span class="token punctuation">（</span> <span class="token number">4、2、8、6</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span><span class="token number">​</span><span class="token punctuation">​</span><span class="token number">​</span><span class="token punctuation">​</span><span class="token number">​</span>
<span class="token function"></span></span><mark><span class="token function">usort</span> <span class="token punctuation">（</span> <span class="token variable">$ 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>

自分で試してみてください