Here is one way:
def rotate(strg, n):
return strg[n:] + strg[:n]
rotate('HELLO', -1) # 'OHELL'
Alternatively, collections.deque
(“double-ended queue”) is optimised for queue-related operations. It has a dedicated rotate() method:
from collections import deque
items = deque('HELLO')
items.rotate(1)
''.join(items) # 'OHELL'