PHP Array Exercises : Create a letter range with arbitrary length

<?php
// Define a function named letter_range that takes a length as input
function letter_range($length)
{
    // Initialize an empty array to store the result
    $data_range = array();
    
    // Create an array of uppercase letters from 'A' to 'Z'
    $letters = range('A', 'Z');
    
    // Iterate through the specified length
    for($i=0; $i<$length; $i++)
    {
        // Calculate the starting position for each iteration
        $position = $i * 26;
        
        // Iterate through the letters and generate combinations
        foreach($letters as $ii => $letter)
        {
            // Increment the position
            $position++;
            
            // Check if the position is within the specified length
            if($position <= $length)
                // Add the generated combination to the result array
                $data_range[] = ($position > 26 ? $data_range[$i-1] : '').$letter;
        }
    }
    
    // Return the array containing the generated letter combinations
    return $data_range;
}

// Test the function with a length of 7 and print the result
print_r(letter_range(7));

?>