This works fine too, dict((k, []) for k in keys) Although I later realized what I really needed was defaultdict[1] d = defaultdict(list) [1]: http://d

This works fine too, dict((k, []) for k in keys) Although I later realized what I really needed was defaultdict[1] d = defaultdict(list) [1]: http://docs.python.org/2/library/collections.html#collections.defaultdict http://docs.python.org/2/library/collections.html#collection...