3-otedama.py

# -*- coding: utf-8 -*-
def rotate_arr(arr, t):
    """programming peals

    rotate array algorithm(destructive)"""
    l = len(arr)
    tmp = arr[0]
    k = 0
    while True:
        j = k
        k = j+t
        if k > l-1: k -= l
        if k == 0:
            arr[j] = tmp
            break
        arr[j] = arr[k]
    return arr

a = [1,2,3,4,5]
print rotate_arr(a, 2)                  # => [3,4,5,1,2]