python .lower() is not working [duplicate]

Question

I don't know what I'm doing wrong, but the function .lower() in my python code is not working!

It's a sily code, but it does not lower de cases of the word:

score = {"a": 1, "c": 3, "b": 3, "e": 1, "d": 2, "g": 2, 
         "f": 4, "i": 1, "h": 4, "k": 5, "j": 8, "m": 3, 
         "l": 1, "o": 1, "n": 1, "q": 10, "p": 3, "s": 1, 
         "r": 1, "u": 1, "t": 1, "w": 4, "v": 4, "y": 4, 
         "x": 8, "z": 10}

def scrabble_score(word):
    word.lower()
    print word
    total =0
    for i in word:
        total += score[i]
    return total

print scrabble_score('Helix')    

some help?

Answer 1

You have to assign the result of lower() back to word as strings are immutable:

In [152]:

score = {"a": 1, "c": 3, "b": 3, "e": 1, "d": 2, "g": 2, 
         "f": 4, "i": 1, "h": 4, "k": 5, "j": 8, "m": 3, 
         "l": 1, "o": 1, "n": 1, "q": 10, "p": 3, "s": 1, 
         "r": 1, "u": 1, "t": 1, "w": 4, "v": 4, "y": 4, 
         "x": 8, "z": 10}

def scrabble_score(word):
    word = word.lower() #<------ here assign back
    print(word)
    total =0
    for i in word:
        total += score[i]
    return total

print(scrabble_score('Helix'))

helix
15

See related: Why are Python strings immutable? Best practices for using them

Answer 2

Do:

word = word.lower()

because lower() doesn't modify original string