>>> a = {0:'000000',1:'11111',3:'333333',4:'444444'} >>> a.keys() [0, 1, 3, 4] >>> sorted(a.keys()) [0, 1, 3, 4] >>> reversed(sorted(a.keys())) <listreverseiterator object at 0x02B0DB70> >>> list(reversed(sorted(a.keys()))) [4, 3, 1, 0]