How Can I Change The Case In Python To Make Upper Case Lower And Vice Versa

Topic 7: Question 4 Write the function changeCase(word) that changes the case of all the letters in a word and returns the new word. Examples >>> changeCase('aPPle') 'AppL

Solution 1:

Use str.swapcase:

>>> 'aPPle'.swapcase()
'AppLE'
>>> 'BaNaNa'.swapcase()
'bAnAnA'

Solution 2:

My solution to the problem, no need to "manually" change a case of a letter as above.

def changeCase(word):
    newword = ""                     # Create a blank string
    for i in range(0, len(word)):
        character = word[i]          # For each letter in a word, make as individual viarable
        if character.islower()== False: # Check if a letter in a string is already in upper case
            character = character.lower()  # Make a letter lower case
            newword += character           # Add a modified letter in a new string
        else:
            character = character.upper()  # Make a letter upper case
            newword += character           # Add a modified letter in a new string

    return newword                         # Return a new string

Solution 3:

def swap_case(s):
    input_list = list(s)
    return "".join(i.lower() if i in "ABCDEFGHIJKLMNOPQRSTUVWXYZ" else i.upper() for i in input_list)

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

Solution 4:

#Here is another example to convert lower case to upper case and vice versa   
while not bothering other characters:
#Defining function
def swap_case(s):
    ls=[]
    str=''
    # converting each character from lower case to upper case and vice versa and appending it into list
    for i in range(len(s)):
        if ord(s[i]) >= 97:
            ls.append(chr((ord(s[i]))-32)) #ord() and chr() are inbuild methods
        elif ord(s[i]) >= 65 and ord(s[i]) <97:
             ls.append(chr((ord(s[i]))+32))
        # keeping other characters
        else:
            ls.append(chr(ord(s[i])))
    # converting list into string
    for i in ls:
        str+=i
    return(str)
if __name__ == '__main__':
    s = input()
    # calling function swap_case()
    result = swap_case(s)
    print(result)


input: www.SWAPCASE@program.2
Output: WWW.swapcase@PROGRAM.2

Solution 5:

let="alpHabET"

print(let.swapcase())

#o/p == ALPhABet