>>> a = [1,2,3] >>> b = [2,4,5] >>> list(set(a).intersection(set(b))) [2] >>> list(set(a).union(set(b))) [1, 2, 3, 4, 5] >>> list(set(a).difference(set(b))) [1, 3] >>> list(set(b).difference(set(a))) [4, 5] >>>