bool is_file ( string $filename ) $file 为必选参数

来看一个测试is_file经典实例

<?php教程
var_dump(is_file('a_file.txt')) . " ";
var_dump(is_file('/usr/bin/')) . " ";
?>

输也值

ture

false

用法二

<?php
function isfile($file){
    return preg_match('/^[^.^:^?^-][^:^?]*.(?i)' . getexts() . '$/',$file);
    //first character cannot be . : ? - subsequent characters can't be a : ?
    //then a . character and must end with one of your extentions
    //getexts() can be replaced with your extentions pattern
}

function getexts(){
    //list acceptable file extensions here
    return '(app|avi|doc|docx|exe|ico|mid|midi|mov|mp3|
                 mpg|mpeg|pdf|psd|qt|ra|ram|rm|rtf|txt|wav|word|xls)';
}

echo isfile('/Users/YourUserName/Sites/index.html');
?>

实例三

<?php
  function deletefolder($path)
  {
    if ($handle=opendir($path))
    {
      while (false!==($file=readdir($handle)))
      {
        if ($file<>"." AND $file<>"..")
        {
          if (is_file($path.'/'.$file))
          {
            @unlink($path.'/'.$file);
          }
          if (is_dir($path.'/'.$file))
          {
            deletefolder($path.'/'.$file);
            @rmdir($path.'/'.$file);
          }
        }
      }
    }
  }
?>
此函数删除所有事情，定义的文件夹：
工程与PHP 4和5。