Yingjie Lin <yingjie....@mssm.edu> writes: > I have two lists: > > li1 = ['a', 'b'] > li2 = ['1', '2'] > > and I wish to obtain a list like this > > li3 = ['a1', 'a2', 'b1', 'b2'] > > Is there a handy and efficient function to do this, especially when > li1 and li2 are long lists.
It's not difficult to write your own: def product(l1,l2): for x1 in l1: for x2 in l2: yield x1+x2 use it like: for p in product(l1,l2) ... The call to product() produces a generator, the cross product is never built in full, it should work on long lists. -- Alain. -- http://mail.python.org/mailman/listinfo/python-list