In article <34fc571c-f382-405d-94b1-0a673da5f...@t16g2000vbi.googlegroups.com>, SigmundV <sigmu...@gmail.com> wrote:
> I think the OP wants to find the intersection of two lists. > list(set(list1) & set(list2)) is indeed one way to achieve this. [i > for i in list1 if i in list2] is another one. Both ways work, but the first is O(n) and the second is O(n^2). import time n = 10000 list1 = range(n) list2 = range(n) t0 = time.time() list(set(list1) & set(list2)) t1 = time.time() print "list(set) method took %f seconds" % (t1 - t0) t0 = time.time() [i for i in list1 if i in list2] t1 = time.time() print "loop method took %f seconds" % (t1 - t0) ./intersect.py 100000 list(set) method took 0.004791 seconds loop method took 1.437322 seconds -- http://mail.python.org/mailman/listinfo/python-list
