''.join(seen.add(c) or c for c in s if c not in seen) >From what I can understand...
.join will be a String of unique 'c' values. 'seen.add(c) or c' will always point to the second statement 'c' because seen.add(c) returns None. 'if c not in seen' will ensure 'c' being added to both the .join and seen is unique. That is really clever! I like it :) (but does require a bit of knowledge about .add return None and the affect that has on the .. or .. statement) -- http://mail.python.org/mailman/listinfo/python-list
