file_exists
检查文件或目录是否存在
<span class="token php language-php"><span class="token delimiter important"><?php</span> <span class="token keyword">echo</span> <span class="token function">file_exists</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"test.txt"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token delimiter important">?></span></span>
输出:
1