# Copyright 2014-2020 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.distance._prefix.
Prefix similarity & distance
"""
from deprecation import deprecated
from ._distance import _Distance
from .. import __version__
__all__ = ['Prefix', 'dist_prefix', 'sim_prefix']
[docs]class Prefix(_Distance):
"""Prefix similiarity and distance.
.. versionadded:: 0.3.6
"""
[docs] def sim(self, src, tar):
"""Return the prefix similarity of two strings.
Prefix similarity is the ratio of the length of the shorter term that
exactly matches the longer term to the length of the shorter term,
beginning at the start of both terms.
Parameters
----------
src : str
Source string for comparison
tar : str
Target string for comparison
Returns
-------
float
Prefix similarity
Examples
--------
>>> cmp = Prefix()
>>> cmp.sim('cat', 'hat')
0.0
>>> cmp.sim('Niall', 'Neil')
0.25
>>> cmp.sim('aluminum', 'Catalan')
0.0
>>> cmp.sim('ATCG', 'TAGC')
0.0
.. versionadded:: 0.1.0
.. versionchanged:: 0.3.6
Encapsulated in class
"""
if src == tar:
return 1.0
if not src or not tar:
return 0.0
min_word, max_word = (src, tar) if len(src) < len(tar) else (tar, src)
min_len = len(min_word)
for i in range(min_len, 0, -1):
if min_word[:i] == max_word[:i]:
return i / min_len
return 0.0
[docs]@deprecated(
deprecated_in='0.4.0',
removed_in='0.6.0',
current_version=__version__,
details='Use the Prefix.sim method instead.',
)
def sim_prefix(src, tar):
"""Return the prefix similarity of two strings.
This is a wrapper for :py:meth:`Prefix.sim`.
Parameters
----------
src : str
Source string for comparison
tar : str
Target string for comparison
Returns
-------
float
Prefix similarity
Examples
--------
>>> sim_prefix('cat', 'hat')
0.0
>>> sim_prefix('Niall', 'Neil')
0.25
>>> sim_prefix('aluminum', 'Catalan')
0.0
>>> sim_prefix('ATCG', 'TAGC')
0.0
.. versionadded:: 0.1.0
"""
return Prefix().sim(src, tar)
[docs]@deprecated(
deprecated_in='0.4.0',
removed_in='0.6.0',
current_version=__version__,
details='Use the Prefix.dist method instead.',
)
def dist_prefix(src, tar):
"""Return the prefix distance between two strings.
This is a wrapper for :py:meth:`Prefix.dist`.
Parameters
----------
src : str
Source string for comparison
tar : str
Target string for comparison
Returns
-------
float
Prefix distance
Examples
--------
>>> dist_prefix('cat', 'hat')
1.0
>>> dist_prefix('Niall', 'Neil')
0.75
>>> dist_prefix('aluminum', 'Catalan')
1.0
>>> dist_prefix('ATCG', 'TAGC')
1.0
.. versionadded:: 0.1.0
"""
return Prefix().dist(src, tar)
if __name__ == '__main__':
import doctest
doctest.testmod()