Efficient way to shift 2D-matrices in both directions?

Question

Given a two dimensional matrix, e.g.

l = [[1,1,1],
     [2,5,2],
     [3,3,3]])

What is the most efficient way of implementing a shift operatio

Answer 1

This is a generic version you can rotate it in all four directions, any number of times

l = [[1,1,1],
     [2,5,2],
     [3,3,3]]

def shift(direction, count, myList):
    myLen = len(myList)
    if direction == "up":
        return [myList[i % myLen] for i in range(count, count + myLen)]
    elif direction == "down":
        return [myList[-i] for i in range(count, count - myLen, -1)]
    elif direction == "left":
        tlist = zip(*myList)
        return map(list, zip(*[tlist[i % myLen] for i in range(count, count + myLen)]))
    elif direction == "right":
        tlist = zip(*myList)
        return map(list, zip(*[tlist[-i] for i in range(count, count - myLen, -1)]))

print shift("up", 1, l)
print shift("up", 2, l)
print shift("down", 2, l)
print shift("down", 1, l)
print shift("left", 1, l)
print shift("right", 1, l)

Output

[[2, 5, 2], [3, 3, 3], [1, 1, 1]]
[[3, 3, 3], [1, 1, 1], [2, 5, 2]]
[[2, 5, 2], [3, 3, 3], [1, 1, 1]]
[[3, 3, 3], [1, 1, 1], [2, 5, 2]]
[[1, 1, 1], [5, 2, 2], [3, 3, 3]]
[[1, 1, 1], [2, 2, 5], [3, 3, 3]]