<?php
$mystring = "A1B22C333";
$pattern = '~(?=\D)~';
$arr = preg_split($pattern, $mystring, -1, PREG_SPLIT_NO_EMPTY
);
PD9waHAKCiRteXN0cmluZyA9ICJBMUIyMkMzMzMiOwokcGF0dGVybiAgPSAnfig/PVxEKX4nOwokYXJyID0gcHJlZ19zcGxpdCgkcGF0dGVybiwgJG15c3RyaW5nLCAtMSwgUFJFR19TUExJVF9OT19FTVBUWSk7CnByaW50X3IoJGFycik7