Kay Schluehr <kay.schlu...@gmx.net> writes: > On 29 Apr., 05:41, Ross <ross.j...@gmail.com> wrote: >> 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] ? >> >> The reason I ask is because I have a generator function that generates >> a list of tuples and I would like to divide this list into >> complementary lists. > > z = [u for u in x if u not in y] > > or > > z = [u for u in x if u not in set(y)]
The above will evaluate set(y) for each element in x. s = set(y) z = [u for u in x if u not in s] -- Arnaud -- http://mail.python.org/mailman/listinfo/python-list
