You can use the range() function to generate an array of alphabets.
Here is an example:
<?php# create an array of alphabets (a-z)$alpha_array = range('a', 'z');print_r($alpha_array);# create an array of alphabets (A-Z)$alpha_array = range('A', 'Z');print_r($alpha_array);?>
You can also use the chr() function to return characters from ASCII values.
E.g.
<?php# list alphabets (a-z)for($i=0; $i<26; $i++){ print(chr(97+$i));}echo "\n";# list alphabets (A-Z)for($i=0; $i<26; $i++){ print(chr(65+$i));}echo "\n";?>