PHP directory traversal operation

* Directory traversal operation:

* 1. Traditional process functions: opendir(), readdir(), closedir()

* 2. Directory scanner: scandir()

* The first way: traditional directory function

* The first step: opendir('directory') opens the directory, returns the resource successfully, returns false on failure

* The second step : readdir($dir) reads the directory content, Shigong returns the file name, and returns false on failure

* The third step: closedir($dir) closes the current directory

$dir = opendir('../0418') or die('打开失败');
// $dir = opendir('./') or die('打开失败');  //.或./当前目录
while (false != ($file = readdir($dir))) {
// print $file."<br>";
// print nl2br($file."\n");
if ($file != "." && $file != "..") {      
print $file."<br>";
     }
}
closedir($dir);
echo &#39;<hr>&#39;;

* The second type Method: Save the directory contents into an array for traversal

* The first step: scandir($dir) converts the directory into an array and saves it

* The second step: Traverses the directory array

//Read the contents of a directory into an array:

$fileArr = scandir('../0417/');
// print_r($fileArr);
foreach ($fileArr as $file) {
if ($file != "." && $file != "..") {
        echo "$file<br>";
     }
}

//Explanation: If you want to recurse all directories, you need to write a custom function to solve the problem. We introduce a more convenient recursive traversal technology.