Ross <ross.jett at gmail.com> writes: > If I have a list x = [1,2,3,4,5,6,7,8,9] and another list that is a > subset of x: y = [1,4,7] , is there a quick way that I could return > the complementary subset to y.... z=[2,3,5,6,8,9] ? >>> x = [1,2,3,4,5,6,7,8,9] >>> y = [1,4,7] >>> print sorted(set(x)-set(y)) [2, 3, 5, 6, 8, 9]