> I have a string of letters and i am tring to count each letter in the string?

I have a string of letters and i am tring to count each letter in the string?

Posted at: 2014-12-18 
I am currently using python doing a program that will keyword compress using run length encoding (sorry for the bad grammar).

so lets say I have this set of characters:

"AAABBBCCCDDE"

How can I work with python to return the number of letters there are (ex: *A3) in the character set?

By the way, I only know pretty much the basics of python. lol please help!