intersection

Find intersection of two nested lists? Question: I know how to get an intersection of two flat lists: b1 = [1,2,3,4,5,9,11,15] b2 = [4,5,6,7,8] b3 = [val for val in b1 if val in b2] or def intersect(a, b): return list(set(a) & set(b)) print intersect(b1, b2) But when I have to find intersection for nested …