Python 3 homework string help

Question

This si what I'm supposed to do.

Define a function named encrypt(msg) that takes a string message as the argument, and returns the message in an "encrypted" form using the encryption rules described below:

1. If the character is an uppercase: change it to lowercase with '!' sign on its both sides (e.g. 'M' --> '!m!');
2. If the character is a lowercase: change it to uppercase with '!' sign on its both sides (e.g. 'm' --> '!M!');
3. If the character is a digit: cube the digit, i.e. raise to the power of 3 (e.g. '5' --> '125');
4. If the character is a blank space: replace it with '$' symbol;
5. Otherwise: keep it as it is.

Examples:

encrypt('500 Miles') returns '12500$!m!!I!!L!!E!!S!'

encrypt('Tesla Model 3.') returns '!t!!E!!S!!L!!A!$!m!!O!!D!!E!!L!$27.'

encrypt('go-2-sky') returns '!G!!O!-8-!S!!K!!Y!'

this is my current code

def encrypt(msg):

  encrypted_msg = " "

  for str in msg:

    if str.isupper():

      encrypted_msg += "!" + str.lower() + "!"

    elif str.islower():

      encrypted_msg += "!" + str.upper() + "!"

    elif str.isdigit():

      encrypted_msg += str(int(str) ** 3)

    elif str.isspace():

      encrypted_msg += "$"

    else:

      encrypted_msg += str

    return encrypted_msg

My current code only return the first letter of the message like for the 2nd example it will return only !t! I need it to return the whole message. How do I fix this?

Answer 1

In your original code, the return was inside the "for" loop, so it returned after only one iteration of the loop. Adjust your indents so that the "return" statement is outside the "for" loop, but still inside your function. I exaggerated the indentations on your original code so that you can see it more clearly.

def encrypt(msg):

   encrypted_msg = " "

for str in msg:

     if str.isupper():

       encrypted_msg += "!" + str.lower() + "!"

     elif str.islower():

      encrypted_msg += "!" + str.upper() + "!"

     elif str.isdigit():

       encrypted_msg += str(int(str) ** 3)

     elif str.isspace():

       encrypted_msg += "$"

     else:

       encrypted_msg += str

return encrypted_msg # no longer in the for loop, but still in the function definition

Answer 2

The issue with your current code is that the return statement is inside the for loop. This means that the function will return the encrypted version of the first character in the message, and then exit the loop and the function. To fix this, you need to move the return statement outside of the for loop, like this:

def encrypt(msg):

encrypted_msg = ""

for str in msg:

if str.isupper():

encrypted_msg += "!" + str.lower() + "!"

elif str.islower():

encrypted_msg += "!" + str.upper() + "!"

elif str.isdigit():

encrypted_msg += str(int(str) ** 3)

elif str.isspace():

encrypted_msg += "$"

else:

encrypted_msg += str

return encrypted_msg