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):
    new = ""
    for i in range(len(s)):
        if str.isupper(s[i]):
            new = new + str.lower(s[i])

        elif str.islower(s[i]):
            new = new + str.upper(s[i])

        else:
            new = new + str(s[i])
        
    return (new)

if __name__ == '__main__':
    s = input()
    result = swap_case(s)
    print(result)

Answer 2

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

Answer 3

Python-3 in-built swapcase function.

def swap_case(s):
    return s.swapcase()

if __name__ == '__main__':
    s = input()
    result = swap_case(s)
    print(result)

Input:

"Pythonist 3"

Output:

"pYTHONIST 3"

Answer 4

As said in comments and othe answers, strings are immutable.

Try following:

s = input("Enter input: ")


def convert(ss):
    # Convert it into list and then change it
    newSS = list(ss)
    for i,c in enumerate(newSS):
        newSS[i] = c.upper() if c.islower() else c.lower()
    # Convert list back to string
    return ''.join(newSS)

print(s)
print(convert(s))

# Or use string build in method
print (s.swapcase())

Answer 5

def swap_case(s):
    a=" "
    for i in s:
        if i==i.lower():
            a=a+(i.upper())
        else:
            a=a+(i.lower())
    return (a)

Answer 6

The built-in str.swapcase already does this.

def swap_case(s):
    return s.swapcase()