pset6: faulty encryption in caesar.py

Question

Please help! My programme is outputting random strings, mixing up lower and upper case, and weirdest of all, it refuses to print plainText input as it is when it's not a letter - it insists on modifying it by key, which is hilarious since it doesn't modify textual output correctly by key.

Is there something I have misunderstood about scope in Python? Or is this about unicode? I just can't for the life of me see where the bug is.

The relevant excerpt of my code is below:

// check usage

// get key, modulo by 26

// get plainText

for i in range(len(plainText)):

# if not a letter, just print
if plainText[i].isalpha == False:
    print("{}".format(plainText[i]), end="")

# if uppercase text, wraparound 90
elif plainText[i].isupper:
    cipher = ord(plainText[i]) + key
    if cipher > 90:
        cipher -= 26
    print("{}".format(chr(cipher)), end="")

# if lowercase text, wraparound 122           
elif plainText[i].islower:
    cipher = ord(plainText[i]) + key
    if cipher > 122:
        cipher -= 26
    print("{}".format(chr(cipher)), end="")

Answer 1

You should call your functions, by adding parentheses ():

if not plainText[i].isalpha():

elif plainText[i].isupper():

elif plainText[i].islower():

Otherwise you refer to the method, which is always interpreted as true