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rotate.py
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"""This module contains a code example related to
Think Python, 2nd Edition
by Allen Downey
http://thinkpython2.com
Copyright 2015 Allen Downey
License: http://creativecommons.org/licenses/by/4.0/
"""
from __future__ import print_function, division
def rotate_letter(letter, n):
"""Rotates a letter by n places. Does not change other chars.
letter: single-letter string
n: int
Returns: single-letter string
"""
if letter.isupper():
start = ord('A')
elif letter.islower():
start = ord('a')
else:
return letter
c = ord(letter) - start
i = (c + n) % 26 + start
return chr(i)
def rotate_word(word, n):
"""Rotates a word by n places.
word: string
n: integer
Returns: string
"""
res = ''
for letter in word:
res += rotate_letter(letter, n)
return res
if __name__ == '__main__':
print(rotate_word('cheer', 7))
print(rotate_word('melon', -10))
print(rotate_word('sleep', 9))