Examining Strings

Hi!
Okay, I am having a little delay here in a card game-in-progress.
I have the 52 cards listed in an array, right?
The 10 of hearts would be
“H10"”
The Jack of spades would be
“SJ”.
So, is there a way to examine the string, and determine the first letter, and then examine the rest of the string? Thanks for your help.