Function rotations

recipes/Python/577574_PythInfinite_Rotations/recipe-577574.py:6–11

rotations([0,1,2]) --> [[0, 1, 2], [1, 2, 0], [2, 0, 1]]

(it)

# First a naive approach. At each generation we pop the first element and append
# it to the back. This is highly memmory deficient.
def rotations(it):
    """ rotations([0,1,2]) --> [[0, 1, 2], [1, 2, 0], [2, 0, 1]] """
    l = list(it)
    for i in range(len(l)):
        yield iter(l)
        l = l[1:]+[l[0]]

# A much better approach would seam to be using a deque, which rotates in O(1),
# However this does have the negative effect, that generating the next rotation