How to increment letters like numbers in PHP?

In PHP, you can use the ++ operator or the += operator to increment letters, just like you would with numbers. Here's an example:

<?php

$letter = 'a';
$letter++;
echo $letter;

This will output "b".

You can also use the += operator to increment the letter by a certain amount. To achieve the desired result, you need to convert the string to its ASCII code, perform the arithmetic operation, and then convert the result back to a string

<?php

$letter = 'a';
$letter = ord($letter) + 3;
$letter = chr($letter);
echo $letter;

This will output "d".

Note that this only works for single-character strings containing letters of the English alphabet in lowercase, and it will wrap around at 'z' and 'Z'.