php directory processing function

Before we dealt with all files, how to deal with directories and folders?

Let’s learn the functions related to the processing of directories or folders.

The basic idea of ​​processing folders is as follows:

1. When reading a certain path, determine whether it is a folder

2. If it is a folder, open the specified file Folder, return the resource variable of the file directory

3. Use readdir to read the file in the directory once, and the directory pointer will be offset backward once

4. Use readdir to read to the end, there is no available The read file returns false

5. Close the file directory

Let’s learn a list of commonly used functions:

<?php
//设置打开的目录是D盘
$dir = "d:/";

//判断是否是文件夹，是文件夹
if (is_dir($dir)) {
   if ($dh = opendir($dir)) {

      //读取一次向后移动一次文件夹指针
      echo readdir($dh).'<br />';
      echo readdir($dh).'<br />';
      echo readdir($dh).'<br />';
      echo readdir($dh).'<br />';

      //读取到最后返回false

      //关闭文件夹资源
       closedir($dh);
   }
}
?>

<?php
//设置打开的目录是D盘
$dir = "d:/";

//判断是否是文件夹，是文件夹
if (is_dir($dir)) {
   if ($dh = opendir($dir)) {


      //读取到最后返回false，停止循环
      while (($file = readdir($dh)) !== false) {
           echo "文件名为: $file : 文件的类型是: " . filetype($dir . $file) . "<br />";
       }

       closedir($dh);
   }
}
?>