# 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._length.
Length similarity & distance
"""
from ._distance import _Distance
__all__ = ['Length']
[docs]
class Length(_Distance):
"""Length similarity and distance.
.. versionadded:: 0.3.6
"""
[docs]
def sim(self, src: str, tar: str) -> float:
"""Return the length similarity of two strings.
Length similarity is the ratio of the length of the shorter string to
the longer.
Parameters
----------
src : str
Source string for comparison
tar : str
Target string for comparison
Returns
-------
float
Length similarity
Examples
--------
>>> cmp = Length()
>>> cmp.sim('cat', 'hat')
1.0
>>> cmp.sim('Niall', 'Neil')
0.8
>>> cmp.sim('aluminum', 'Catalan')
0.875
>>> cmp.sim('ATCG', 'TAGC')
1.0
.. 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
return (
len(src) / len(tar) if len(src) < len(tar) else len(tar) / len(src)
)
if __name__ == '__main__':
import doctest
doctest.testmod()