Hello, I am trying to accomplish the following:
Say I have a group of 4 lists as follows: l1 = ['a1', 'a2', 'a3', 'a4'] l2 = ['b1', 'b2', 'b3', 'b4'] l3 = ['c1', 'c2', 'c3', 'c4'] l4 = ['d1', 'd2', 'd3', 'd4'] I would like to cycle through these lists "diagonally" in groups of len(list) (in this example, each list has 4 items). cycle1: a1, b2, b3, b4 cycle2: a2, b3, c4, d1 cycle3: a3, b4, c1, d2 cycle4: a4, b1, c2, d3 The way I thought about doing this is as follows: from collections import deque from itertools import cycle l1 = deque(['a1', 'a2', 'a3', 'a4']) l2 = deque(['b1', 'b2', 'b3', 'b4']) l3 = deque(['c1', 'c2', 'c3', 'c4']) l4 = deque(['d1', 'd2', 'd3', 'd4']) l1.rotate(-0) l2.rotate(-1) l3.rotate(-2) l4.rotate(-3) groups = cycle([l1, l2, l3, l4]) In [115]: for group in groups: .....: if not group: .....: break .....: print(group.popleft()) .....: a1 b2 c3 d4 a2 b3 c4 d1 a3 b4 c1 d2 a4 b1 c2 d3 Prior to this I was mucking around with index counting while looping, and popping lists out of a deque, popping an item out of the list, and appending the list back into the deque during each iteration. Is there a better/cleaner way to do this? I was hoping for some cool itertools logic =) Thanks! -- *Pablo* -- https://mail.python.org/mailman/listinfo/python-list
