Source code for abydos.fingerprint._count

# Copyright 2018-2020 by Christopher C. Little.
# This file is part of Abydos.
#
# Abydos is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Abydos is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
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"""abydos.fingerprint._count.

Cisłak & Grabowski's count fingerprint
"""

from collections import Counter
from typing import Tuple

from ._fingerprint import MOST_COMMON_LETTERS_CG, _Fingerprint

__all__ = ['Count']


[docs]class Count(_Fingerprint): """Count Fingerprint. Based on the count fingerprint from :cite:`Cislak:2017`. .. versionadded:: 0.3.6 """ def __init__( self, n_bits: int = 16, most_common: Tuple[str, ...] = MOST_COMMON_LETTERS_CG, ) -> None: """Initialize Count instance. Parameters ---------- n_bits : int Number of bits in the fingerprint returned most_common : list The most common tokens in the target language, ordered by frequency .. versionadded:: 0.4.0 """ super(Count, self).__init__() self._n_bits = n_bits self._most_common = most_common
[docs] def fingerprint(self, word: str) -> str: """Return the count fingerprint. Parameters ---------- word : str The word to fingerprint Returns ------- str The count fingerprint Examples -------- >>> cf = Count() >>> cf.fingerprint('hat') '0001010000000001' >>> cf.fingerprint('niall') '0000010001010000' >>> cf.fingerprint('colin') '0000000101010000' >>> cf.fingerprint('atcg') '0001010000000000' >>> cf.fingerprint('entreatment') '1111010000100000' .. versionadded:: 0.3.0 .. versionchanged:: 0.3.6 Encapsulated in class .. versionchanged:: 0.6.0 Changed to return a str and added fingerprint_int method """ return ('{:0' + str(self._n_bits) + 'b}').format( self.fingerprint_int(word) )
[docs] def fingerprint_int(self, word: str) -> int: """Return the count fingerprint. Parameters ---------- word : str The word to fingerprint Returns ------- int The count fingerprint as an int Examples -------- >>> cf = Count() >>> cf.fingerprint_int('hat') 5121 >>> cf.fingerprint_int('niall') 1104 >>> cf.fingerprint_int('colin') 336 >>> cf.fingerprint_int('atcg') 5120 >>> cf.fingerprint_int('entreatment') 62496 .. versionadded:: 0.6.0 """ n_bits = self._n_bits if n_bits % 2: n_bits += 1 letter_counts = Counter(word) fingerprint = 0 for letter in self._most_common: if n_bits: fingerprint <<= 2 fingerprint += letter_counts[letter] & 3 n_bits -= 2 else: break if n_bits: fingerprint <<= n_bits return fingerprint
if __name__ == '__main__': import doctest doctest.testmod()