PHP Recursive function: Get all files and directories within a directory and its sub-directories

Question 1

Switch $path with your path, and this should work. The SPL contains all the classes required for recursive directory traversal, there is no need to roll your own.

<?php

$path   = '.';
$result = array('files' => array(), 'directories' => array());

$DirectoryIterator = new RecursiveDirectoryIterator($path);
$IteratorIterator  = new RecursiveIteratorIterator($DirectoryIterator, RecursiveIteratorIterator::SELF_FIRST);
foreach ($IteratorIterator as $file) {

    $path = $file->getRealPath();
    if ($file->isDir()) {
        $result['directories'][] = $path;
    } elseif ($file->isFile()) {
        $result['files'][] = $path;
    }

}

print_r($result);

For more information, consult the PHP documentation: RecursiveDirectoryIterator, RecursiveIteratorIterator & SplFileInfo are great starting points!

Question 2

Using the FilesystemIterator may be a bit faster:

function getDirectoryList($dir) {
    $dirList = $fileList = array();
    $iter = new FilesystemIterator($dir, FilesystemIterator::SKIP_DOTS);

    foreach($iter as $file) {
        if($file->isDir()) {
            $dirList[$file->getFilename()] = getDirectoryList($file->getPathname());
        } else {
            $fileList[$file->getFilename()] = $file->getFilename();
        }
    }
    uksort($dirList, "strnatcmp");
    natsort($fileList);
    return $dirList + $fileList;
}

This function will give you a multi-dimensional array structured exactly like your directory structure, which may also be easier to work with.

Question 3

You should either assign the "arr" returning from the recusive call OR you should pass in the array by reference. (see passing by reference: http://php.net/manual/en/language.references.pass.php)

To pass by reference: get_files_directories($new_dir, &$arr);

Question 4

It's a recursive call and you might append the return value to the array or work on a array reference:

if(is_dir($new_dir))
{
    $arr['directories'][] = $new_dir;
    get_files_directories($new_dir, $arr); //assign or return
}

-

function get_files_directories($directory, &$arr)