Efficient way to rotate a list in python

Question

What is the most efficient way to rotate a list in python? Right now I have something like this:

>>> def rotate(l, n):
...     return l[n:] + l[:n]         


        

Answer 1

The following method is O(n) in place with constant auxiliary memory:

def rotate(arr, shift):
  pivot = shift % len(arr)
  dst = 0
  src = pivot
  while (dst != src):
    arr[dst], arr[src] = arr[src], arr[dst]
    dst += 1
    src += 1
    if src == len(arr):
      src = pivot
    elif dst == pivot:
      pivot = src

Note that in python, this approach is horribly inefficient compared to others as it can't take advantage of native implementations of any of the pieces.