Quelle est la différence entre la fonction is_readable et la fonction IS_FILE dans PHP? À quels scénarios d'application conviennent-ils?

<span><span><span class="hljs-meta"><?php</span></span><span> </span><span><span class="hljs-comment">// 这是与文章内容无关的前置PHP代码示例</span></span><span> </span><span><span class="hljs-title function_ invoke__">date_default_timezone_set</span></span><span>(</span><span><span class="hljs-string">'Asia/Shanghai'</span></span><span>); </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"当前时间："</span></span><span> . </span><span><span class="hljs-title function_ invoke__">date</span></span><span>(</span><span><span class="hljs-string">'Y-m-d H:i:s'</span></span><span>) . </span><span><span class="hljs-string">"\n"</span></span><span>; </span><span><span class="hljs-meta">?></span></span><span> <hr> </span><span><span class="hljs-meta"><?php</span></span><span> <span class="hljs-comment">/* 文章正文开始 标题: PHP中is_readable函数和is_file函数有什么区别？它们各自适合哪些应用场景？ */</span> </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h1>PHP中is_readable函数和is_file函数的区别及应用场景</h1>"</span></span><span>; </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<p>在PHP开发中，经常需要判断文件或目录的状态，以便决定后续操作是否可行。<strong>is_readable()</strong>和<strong>is_file()</strong>是两个常用的文件判断函数，它们的功能和适用场景有所不同。</p>"</span></span><span>; </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>一、is_readable()函数</h2>"</span></span><span>; </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<p><code>is_readable(string <span class="hljs-subst">$filename</span></span></span><span>): bool ';; écho "

Scénarios applicables:

$ filename = "example.txt";
if (is_file ($ filename)) {
    Echo "Ceci est un fichier";
} autre {
    Echo "Ce n'est pas un fichier";
}