use a set to store them:
>>> s=set()
>>> s.add('a')
>>> s.add('b')
>>> s
set(['a', 'b'])
>>> s.add('a')
>>> s
set(['a', 'b'])
>>> s.add('c')
>>> s
set(['a', 'c', 'b'])
>>> it does remove duplicates, but is it not ordered. to order it you can use: >>> l=list(s) >>> l.sort() >>> l ['a', 'b', 'c'] hth, Rares -- http://mail.python.org/mailman/listinfo/python-list
