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]
Following function copies sent list to a templist, so that pop function does not affect the original list:
def shift(lst, n, toreverse=False):
templist = []
for i in lst: templist.append(i)
if toreverse:
for i in range(n): templist = [templist.pop()]+templist
else:
for i in range(n): templist = templist+[templist.pop(0)]
return templist
Testing:
lst = [1,2,3,4,5]
print("lst=", lst)
print("shift by 1:", shift(lst,1))
print("lst=", lst)
print("shift by 7:", shift(lst,7))
print("lst=", lst)
print("shift by 1 reverse:", shift(lst,1, True))
print("lst=", lst)
print("shift by 7 reverse:", shift(lst,7, True))
print("lst=", lst)
Output:
lst= [1, 2, 3, 4, 5]
shift by 1: [2, 3, 4, 5, 1]
lst= [1, 2, 3, 4, 5]
shift by 7: [3, 4, 5, 1, 2]
lst= [1, 2, 3, 4, 5]
shift by 1 reverse: [5, 1, 2, 3, 4]
lst= [1, 2, 3, 4, 5]
shift by 7 reverse: [4, 5, 1, 2, 3]
lst= [1, 2, 3, 4, 5]