PHP Array Exercises : Extension of a file

<?php
// Define a function named file_extension that takes a file path as an argument
function file_extension($str1){
    // Replace backslashes with an empty string in the given path
    $str1 = implode("", explode("\\", $str1));
    
    // Explode the path using the dot as a delimiter to extract the file extension
    $str1 = explode(".", $str1);
    
    // Convert the file extension to lowercase and return it
    $str1 = strtolower(end($str1));
    
    return $str1;
}

// Define a file path 'example.txt'
$file = 'example.txt';

// Call the file_extension function and display the result
echo "\n" . file_extension($file) . "\n";

?>