curriculum/challenges/english/blocks/learn-string-manipulation-by-building-a-cipher/65552a9593755e1fb2f5ab50.md
Define another function named decrypt with the same parameters as encrypt. This time return vigenere(message, key, -1).
You should define a new function called decrypt.
({ test: () => assert(runPython(`
import inspect
inspect.isfunction(decrypt)
`))
})
Your decrypt function should take message and key as the parameters.
({ test: () => assert(runPython(`
import inspect
sig = inspect.signature(decrypt)
str(sig) == "(message, key)"
`))
})
Your decrypt function should return vigenere(message, key, -1).
({ test: () => {
const commentless_code = __helpers.python.removeComments(code);
const {function_body} = __helpers.python.getDef(commentless_code, "decrypt");
assert(function_body.match(/return\s+vigenere\s*\(\s*message\s*,\s*key\s*,\s*-\s*1\s*\)/));
}
})
text = 'Hello Zaira!'
custom_key = 'python'
def vigenere(message, key, direction=1):
key_index = 0
alphabet = 'abcdefghijklmnopqrstuvwxyz'
final_message = ''
for char in message.lower():
# Append any non-letter character to the message
if not char.isalpha():
final_message += char
else:
# Find the right key character to encode/decode
key_char = key[key_index % len(key)]
key_index += 1
# Define the offset and the encrypted/decrypted letter
offset = alphabet.index(key_char)
index = alphabet.find(char)
new_index = (index + offset*direction) % len(alphabet)
final_message += alphabet[new_index]
return final_message
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def encrypt(message, key):
return vigenere(message, key)
encryption = vigenere(text, custom_key)
print(encryption)
decryption = vigenere(encryption, custom_key, -1)
print(decryption)
--fcc-editable-region--