# 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.
#
# You should have received a copy of the GNU General Public License
# along with Abydos. If not, see <http://www.gnu.org/licenses/>.
"""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()