strcoll

例

文字列を比較してください：

 <span class="token php language-php"><span class="token delimiter important"><？php</span>
<span class="token function">setLocale</span> <span class="token punctuation">（</span> <span class="token constant">lc_collate</span> <span class="token punctuation">、</span> <span class="token string single-quoted-string">&#39;nl&#39;</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span>
<span class="token keyword">Echo</span> <span class="token function">Strcoll</span> <span class="token punctuation">（</span> <span class="token string double-quoted-string">"Hello World！"</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"Hello World！"</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span>
<span class="token keyword">echo</span> <span class="token string double-quoted-string">"<br>"</span> <span class="token punctuation">;</span>

<span class="token function">setLocale</span> <span class="token punctuation">（</span> <span class="token constant">lc_collate</span> <span class="token punctuation">、</span> <span class="token string single-quoted-string">&#39;en_us&#39;</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span>
<span class="token keyword">Echo</span> <span class="token function">Strcoll</span> <span class="token punctuation">（</span> <span class="token string double-quoted-string">"Hello World！"</span> <span class="token punctuation">、</span> <span class="token string double-quoted-string">"Hello World！"</span> <span class="token punctuation">）</span> <span class="token punctuation">;</span>
<span class="token delimiter important">？></span></span>

自分で試してみてください