PHP scandir: Read Directory Contents into an Array

This article provides a straightforward guide on how to use the built-in scandir() function in PHP to read the files and directories of a specific path into an array. You will learn the basic syntax, how to handle the default directory pointers (. and ..), how to sort the output, and how to safely implement this function in your web applications.

Basic Usage of scandir()

The scandir() function in PHP accepts a directory path as its primary argument and returns an array of files and directories found inside that path. If the directory does not exist or cannot be read, it returns false.

Here is the simplest way to use it:

$dir = "./my_directory";

// Read the directory contents into an array
$files = scandir($dir);

// Output the array
print_r($files);

Filtering Out Default Directory Pointers

By default, scandir() includes the current directory (.) and parent directory (..) pointers in the returned array. To clean up your array and only keep actual files and folders, you can use array_diff().

$dir = "./my_directory";

// Scan and filter out '.' and '..'
$files = array_diff(scandir($dir), array('.', '..'));

// Re-index the array keys starting from 0
$files = array_values($files);

print_r($files);

Sorting the Directory Contents

The scandir() function provides a second argument to control the sorting order of the returned array. PHP offers three built-in constants for this purpose:

1. SCANDIR_SORT_ASCENDING (Default): Sorts alphabetically in ascending order.
2. SCANDIR_SORT_DESCENDING: Sorts alphabetically in descending order.
3. SCANDIR_SORT_NONE: Returns the files in the order they are stored by the filesystem.

$dir = "./my_directory";

// Sort descending
$files_desc = scandir($dir, SCANDIR_SORT_DESCENDING);

// No sorting (faster performance for large directories)
$files_unsorted = scandir($dir, SCANDIR_SORT_NONE);

Safe Implementation with Error Handling

To prevent PHP warnings or crashes, always verify that the directory exists and is readable before running scandir().

$dir = "./my_directory";

if (is_dir($dir)) {
    if ($files = scandir($dir)) {
        // Filter out parent and current directory pointers
        $clean_files = array_diff($files, array('.', '..'));
        
        foreach ($clean_files as $file) {
            echo $file . "<br>";
        }
    } else {
        echo "Failed to read directory contents.";
    }
} else {
    echo "Directory does not exist.";
}