Source code for abydos.fingerprint._occurrence

# 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
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#
# Abydos is distributed in the hope that it will be useful,
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# GNU General Public License for more details.
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"""abydos.fingerprint._occurrence.

Cisłak & Grabowski's occurrence fingerprint
"""

from typing import Tuple

from ._fingerprint import MOST_COMMON_LETTERS_CG, _Fingerprint

__all__ = ['Occurrence']


[docs] class Occurrence(_Fingerprint): """Occurrence Fingerprint. Based on the occurrence 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(Occurrence, self).__init__() self._n_bits = n_bits self._most_common = most_common
[docs] def fingerprint(self, word: str) -> str: """Return the occurrence fingerprint. Parameters ---------- word : str The word to fingerprint Returns ------- str The occurrence fingerprint Examples -------- >>> of = Occurrence() >>> of.fingerprint('hat') '0110000100000000' >>> of.fingerprint('niall') '0010110000100000' >>> of.fingerprint('colin') '0001110000110000' >>> of.fingerprint('atcg') '0110000000010000' >>> of.fingerprint('entreatment') '1110010010000100' .. 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 occurrence fingerprint. Parameters ---------- word : str The word to fingerprint Returns ------- int The occurrence fingerprint as an int Examples -------- >>> of = Occurrence() >>> of.fingerprint_int('hat') 24832 >>> of.fingerprint_int('niall') 11296 >>> of.fingerprint_int('colin') 7216 >>> of.fingerprint_int('atcg') 24592 >>> of.fingerprint_int('entreatment') 58500 .. versionadded:: 0.6.0 """ n_bits = self._n_bits fingerprint = 0 for letter in self._most_common: if letter in set(word): fingerprint += 1 n_bits -= 1 if n_bits: fingerprint <<= 1 else: break n_bits -= 1 if n_bits > 0: fingerprint <<= n_bits return fingerprint
if __name__ == '__main__': import doctest doctest.testmod()