Analyzing Folder Contents in PHP

Suppose we have a folder dir, containing both files and folders.

Let's get an array of names from this folder:

<?php
	$files = array_diff(scandir('dir'), ['..', '.']);
?>

Let's check for each name whether it is a file or a folder:

<?php
	$files = array_diff(scandir('dir'), ['..', '.']);
	
	foreach ($files as $file) {
		echo $file;
		var_dump(is_file('dir/' . $file));
	}
?>

Please note that the name of the folder we are scanning is written in two places in the code. This is not very convenient. Let's move this name to a separate variable:

<?php
	$dir = 'dir';
	$files = array_diff(scandir($dir), ['..', '.']);
	
	foreach ($files as $file) {
		echo $file;
		var_dump(is_file($dir. '/' . $file));
	}
?>

Now let's output the contents of all files to the screen:

<?php
	$dir = 'dir';
	$files = array_diff(scandir($dir), ['..', '.']);
	
	foreach ($files as $file) {
		if (is_file($dir. '/' . $file)) {
			echo file_get_contents($dir. '/' . $file);
		}
	}
?>

It can be noticed that the path to the file is calculated twice. Let's move it to a separate variable:

<?php
	$dir = 'dir';
	$files = array_diff(scandir($dir), ['..', '.']);
	
	foreach ($files as $file) {
		$path = $dir. '/' . $file; // file path
		
		if (is_file($path)) {
			echo file_get_contents($path);
		}
	}
?>

A folder is given. Display a column of names of subfolders from this folder.

A folder is given. Display a column of names of files from this folder.

A folder is given. Append the current timestamp to the end of each file in this folder.