Python - All Set for Comparison

I spent entire evening looking for a way to sort the characters in a string and figured it out.

1. Turn the String into List. 
2. Sort it. 
3. Join it back as a String.

And then, I stumbled upon a better way to do string comparison. Convert them to sets!!!

set(stringA).difference(stringB)

Note that it may not be same as
set(stringB).difference(stringA)

Details on set theory here:

http://docs.python.org/library/sets.html#set-objects

Discussion here:

http://stackoverflow.com/questions/1388818/how-can-i-compare-two-lists-in-python-and-return-matches