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Make decrypt_caesar_with_chi_squared work with upper case letters #5379

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Merged
merged 2 commits into from
Oct 31, 2021
Merged

Make decrypt_caesar_with_chi_squared work with upper case letters #5379

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c188578
Fixes: #5323
happiestbee Oct 17, 2021
d47486b
Fixes: #5323
happiestbee Oct 18, 2021
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22 changes: 15 additions & 7 deletions ciphers/decrypt_caesar_with_chi_squared.py
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ def decrypt_caesar_with_chi_squared(
ciphertext: str,
cipher_alphabet: list[str] | None = None,
frequencies_dict: dict[str, float] | None = None,
case_sensetive: bool = False,
case_sensitive: bool = False,
) -> tuple[int, float, str]:
"""
Basic Usage
Expand All @@ -20,7 +20,7 @@ def decrypt_caesar_with_chi_squared(
* frequencies_dict (dict): a dictionary of word frequencies where keys are
the letters and values are a percentage representation of the frequency as
a decimal/float
* case_sensetive (bool): a boolean value: True if the case matters during
* case_sensitive (bool): a boolean value: True if the case matters during
decryption, False if it doesn't

Returns:
Expand Down Expand Up @@ -117,6 +117,9 @@ def decrypt_caesar_with_chi_squared(
>>> decrypt_caesar_with_chi_squared('crybd cdbsxq')
(10, 233.35343938980898, 'short string')

>>> decrypt_caesar_with_chi_squared('Crybd Cdbsxq', case_sensitive=True)
(10, 233.35343938980898, 'Short String')

>>> decrypt_caesar_with_chi_squared(12)
Traceback (most recent call last):
AttributeError: 'int' object has no attribute 'lower'
Expand Down Expand Up @@ -158,7 +161,7 @@ def decrypt_caesar_with_chi_squared(
# Custom frequencies dictionary
frequencies = frequencies_dict

if not case_sensetive:
if not case_sensitive:
ciphertext = ciphertext.lower()

# Chi squared statistic values
Expand All @@ -172,10 +175,14 @@ def decrypt_caesar_with_chi_squared(
for letter in ciphertext:
try:
# Try to index the letter in the alphabet
new_key = (alphabet_letters.index(letter) - shift) % len(
new_key = (alphabet_letters.index(letter.lower()) - shift) % len(
alphabet_letters
)
decrypted_with_shift += alphabet_letters[new_key]
decrypted_with_shift += (
alphabet_letters[new_key].upper()
if case_sensitive and letter.isupper()
else alphabet_letters[new_key]
)
except ValueError:
# Append the character if it isn't in the alphabet
decrypted_with_shift += letter
Expand All @@ -184,10 +191,11 @@ def decrypt_caesar_with_chi_squared(

# Loop through each letter in the decoded message with the shift
for letter in decrypted_with_shift:
if case_sensetive:
if case_sensitive:
letter = letter.lower()
if letter in frequencies:
# Get the amount of times the letter occurs in the message
occurrences = decrypted_with_shift.count(letter)
occurrences = decrypted_with_shift.lower().count(letter)

# Get the excepcted amount of times the letter should appear based
# on letter frequencies
Expand Down