13_Next nth Letter.py

# Write a procedure, shift_n_letters which takes as its input a lowercase
# letter, a-z, and an integer n, and returns the letter n steps in the
# alphabet after it. Note that 'a' follows 'z', and that n can be positive,
# negative or zero.

def shift_n_letters(letter, n):
    # converting into ascii code for easy addition
    asciiletter = ord(letter) - 96
    newletter = (asciiletter + n) % 26 + 96

    return chr(newletter)


print shift_n_letters('s', 1)
# >>> t
print shift_n_letters('s', 2)
# >>> u
print shift_n_letters('s', 10)
# >>> c
print shift_n_letters('s', -10)
# >>> i
print shift_n_letters('z', 1)