Change each character in string to the next character in alphabet

Question

I am coding in Python 2.7 using PyCharm on Ubuntu.

I am trying to create a function that will take a string and change each character to the character that would be

Answer 1

This can be done much easier and efficiently by using a look-up instead of using index for each letter.

look_up = dict(zip(string.ascii_lowercase, string.ascii_lowercase[1:]+'a'))

The zip above creates tuples of the form ('a', 'b')... including ('z', 'a'). Feeding that into the dict constructor makes a dict of the same form.

So now the code can be simply:

def LetterChanges(s):
    from string import ascii_lowercase
    
    look_up = dict(zip(ascii_lowercase, ascii_lowercase[1:]+'a'))
    new_s = ''
    for letter in s:
        new_s += look_up[letter]

    return new_s

---

Even this dict creation and the loop can be saved by using the str.maketrans method and feeding its result to str.translate:

def LetterChanges(s):
    from string import ascii_lowercase

    return s.translate(str.maketrans(ascii_lowercase, ascii_lowercase[1:]+'a'))

Answer 2

this is my code i think it is very simple

def LetterChanges(st):
    index = 0
    new_word = ""
    alphapet = "abcdefghijklmnopqrstuvwxyzacd"

    for i in st.lower():
        if i.islower(): #check if i s letter
            index = alphapet.index(i) + 1 #get the index of the following letter
            new_word += alphapet[index]    
        else: #if not letter
            new_word += i    
    return new_word


print LetterChanges(raw_input())