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90 lines
2.1 KiB
Python
90 lines
2.1 KiB
Python
"""
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Program to encode and decode Baconian or Bacon's Cipher
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Wikipedia reference : https://en.wikipedia.org/wiki/Bacon%27s_cipher
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"""
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encode_dict = {
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"a": "AAAAA",
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"b": "AAAAB",
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"c": "AAABA",
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"d": "AAABB",
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"e": "AABAA",
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"f": "AABAB",
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"g": "AABBA",
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"h": "AABBB",
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"i": "ABAAA",
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"j": "BBBAA",
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"k": "ABAAB",
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"l": "ABABA",
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"m": "ABABB",
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"n": "ABBAA",
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"o": "ABBAB",
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"p": "ABBBA",
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"q": "ABBBB",
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"r": "BAAAA",
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"s": "BAAAB",
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"t": "BAABA",
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"u": "BAABB",
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"v": "BBBAB",
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"w": "BABAA",
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"x": "BABAB",
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"y": "BABBA",
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"z": "BABBB",
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" ": " ",
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}
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decode_dict = {value: key for key, value in encode_dict.items()}
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def encode(word: str) -> str:
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"""
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Encodes to Baconian cipher
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>>> encode("hello")
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'AABBBAABAAABABAABABAABBAB'
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>>> encode("hello world")
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'AABBBAABAAABABAABABAABBAB BABAAABBABBAAAAABABAAAABB'
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>>> encode("hello world!")
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Traceback (most recent call last):
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...
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Exception: encode() accepts only letters of the alphabet and spaces
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"""
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encoded = ""
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for letter in word.lower():
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if letter.isalpha() or letter == " ":
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encoded += encode_dict[letter]
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else:
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raise Exception("encode() accepts only letters of the alphabet and spaces")
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return encoded
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def decode(coded: str) -> str:
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"""
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Decodes from Baconian cipher
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>>> decode("AABBBAABAAABABAABABAABBAB BABAAABBABBAAAAABABAAAABB")
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'hello world'
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>>> decode("AABBBAABAAABABAABABAABBAB")
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'hello'
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>>> decode("AABBBAABAAABABAABABAABBAB BABAAABBABBAAAAABABAAAABB!")
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Traceback (most recent call last):
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...
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Exception: decode() accepts only 'A', 'B' and spaces
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"""
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if set(coded) - {"A", "B", " "} != set():
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raise Exception("decode() accepts only 'A', 'B' and spaces")
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decoded = ""
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for word in coded.split():
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while len(word) != 0:
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decoded += decode_dict[word[:5]]
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word = word[5:]
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decoded += " "
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return decoded.strip()
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if __name__ == "__main__":
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from doctest import testmod
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testmod()
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