How to create letter list alphabetically in PHP according to variable number

If the number of alternatives you need is lower than the letters of the alphabet, you can do so at the expense of range . This function returns an array with all elements ranging from an initial element to an end element defined as function parameters.

Imagining that I wanted 3 alternatives fixedly could do so:

$alternativas = range('a', 'c'); 

If the number of alternatives is dynamic you can also use chr and ord to build the final element dynamically. With ord , get the ASCII value of the initial letter, then increase the desired quantity and get the resulting letter of that number with chr :

$quantidade = 10;
$alternativas = range('a', chr(ord('a') + $quantidade)); 

Output:

Array
(
    [0] => a
    [1] => b
    [2] => c
    [3] => d
    [4] => e
    [5] => f
    [6] => g
    [7] => h
    [8] => i
    [9] => j
    [10] => k
)

See these little examples on Ideone

First you have to have a array with all the letters, for example:

 $letras = ['a', 'b', 'c', 'd'];

After that, just for to go through array of letters.

It would look like this:

<?php
    $alternativas = 2;
    $letras = ['a', 'b', 'c', 'd'];
    if(count($letras) >= $alternativas) { 
        for($n = 0; $n <= $alternativas - 1 ; $n++) {       
            echo $letras[$n];
        }
    }
?>

Since the first index of an array is always 0, I had to subtract 1 from the for loop so that I can get all the indexes correctly.

With this code, I got the following output:

ab

If I had not subtracted -1, the output would be:

abc

I hope this solves your question:

function alternatives($num){

    $letters = array();

    $last = ord('z');

    $letter = ord('a');

    $limit = $letter + $num;

    for($letter = ord('a'); $letter < $limit; $letter++):

        $current = chr($letter);

        $letters[] = $current;

    endfor;

    return implode('<br>', $letters);

}

echo alternatives(3);