Does a "for ... in" loop in Python increase space complexity?

Question

Say I had the following function:

def findNumVowels(s):
    vowels = ['a', 'e', 'i', 'o', 'u']
    numVowels = 0
    for char in s:
        if char in vowels:
            numVowels += 1
    return numVowels

print(findNumVowels("hello world")) # 3

Would the for ... in loop add to the space complexity of this function by creating a new string for each char in s, or is this syntactic sugar that abstracts away the fact that we are accessing a specific index of a string?

Answer 1

No, the loop by itself does not. Consider:

for char in some_string:
    print(char)

It only requires one extra object of constant size. This is constant with respect to the size of the string. So, it doesn't matter if my string is 10 or 1000 characters long, it always requires one extra str to loop over it. Therefore, it takes constant space.