Python, encryption

Question

alpha = 'abcdefghijklmnopqrstuvwxyz '
output = " "
input_mode = ""
while input_mode != 0:
input_mode = input(" [e]ncrypt or [d]ecrypt: ")
if input_mode == 'e':
word = input(" Enter a lowercase word: ")
for letters in word:
indexed = alpha.find(letters)
output += alpha[25-indexed]
print(output)
elif input_mode == 'd':
word = input(" Enter a decryption: ")
for letters in word:
indexed = alpha.find(letters)
output += alpha[25+indexed]
output += alpha[indexed]
print(output)
else:
input_mode != 'e' or input_mode != 'd'
print(" Try again . . . ")
Why does this not work with decryption I want it to go from -25 to 25? Why does it now work?

Answer 1

Your list indices are out of range. In encryption mode, 25-indexed may get in the negative range which is alright because negative list indices are allowed. But 25+indexed in decryption mode doesn't work. You're trying to access element 50+ of a list with only 27 elements. Also, the second line from the bottom is not a valid statement

Answer 2

elif input_mode == 'd':
word = input(" Enter a decryption: ")
for letters in word:
indexed = alpha.find(letters)
output += alpha[25+indexed]
output += alpha[indexed]
print(output)
I'm trying to figure out why this doesn't work? May someone help me.

Answer 3

yeah, i was testing some stuff i figured it out by just making a alpha2 with the alphabet backwards Anna 😂