Swap cases in a string

Question

I\'m trying to solve this challenge in hackerrank, which asks to convert all lowercase letters to uppercase letters and vice versa.

I attempt it with the following code:

Answer 1

def swap_case(s):
    l = list(s)
    for i in range(len(s)):
        if l[i].islower():
            l[i] = l[i].upper()
        else:
            l[i] = l[i].lower()
    k = "".join(map(str,l))
    return k