使用strrev 實現字符串鏡像輸出：如何通過strrev 反轉字符串順序？

gitbox 2025-08-26

<span><span><span class="hljs-comment">// 示例完整代碼</span></span><span>
</span><span><span class="hljs-variable">$example</span></span><span> = </span><span><span class="hljs-string">"PHP字符串鏡像"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"原始: "</span></span><span> . </span><span><span class="hljs-variable">$example</span></span><span> . PHP_EOL;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"反轉: "</span></span><span> . </span><span><span class="hljs-title function_ invoke__">strrev</span></span><span>(</span><span><span class="hljs-variable">$example</span></span><span>) . PHP_EOL; </span><span><span class="hljs-comment">// 注意多字節字符會有問題</span></span><span>
</span></span>

在實際項目中，如果涉及多字節字符串，推薦使用多字節字符串函數來確保反轉正確。

 <span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">mb_strrev</span></span><span>(</span><span><span class="hljs-params"><span class="hljs-variable">$string</span></span></span><span>, </span><span><span class="hljs-variable">$encoding</span></span><span> = </span><span><span class="hljs-string">'UTF-8'</span></span><span>) {
    </span><span><span class="hljs-variable">$length</span></span><span>   = </span><span><span class="hljs-title function_ invoke__">mb_strlen</span></span><span>(</span><span><span class="hljs-variable">$string</span></span><span>, </span><span><span class="hljs-variable">$encoding</span></span><span>);
    </span><span><span class="hljs-variable">$reversed</span></span><span> = </span><span><span class="hljs-string">''</span></span><span>;
    </span><span><span class="hljs-keyword">while</span></span><span> (</span><span><span class="hljs-variable">$length</span></span><span>-- &gt; </span><span><span class="hljs-number">0</span></span><span>) {
        </span><span><span class="hljs-variable">$reversed</span></span><span> .= </span><span><span class="hljs-title function_ invoke__">mb_substr</span></span><span>(</span><span><span class="hljs-variable">$string</span></span><span>, </span><span><span class="hljs-variable">$length</span></span><span>, </span><span><span class="hljs-number">1</span></span><span>, </span><span><span class="hljs-variable">$encoding</span></span><span>);
    }
    </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable">$reversed</span></span><span>;
}

</span><span><span class="hljs-variable">$mbExample</span></span><span> = </span><span><span class="hljs-string">"PHP字符串鏡像"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"多字节反轉: "</span></span><span> . </span><span><span class="hljs-title function_ invoke__">mb_strrev</span></span><span>(</span><span><span class="hljs-variable">$mbExample</span></span><span>) . PHP_EOL;
</span></span>

這樣你就能正確反轉包含中文等多字節字符的字符串，實現真正的鏡像輸出。

strrev