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# -*- coding: utf-8 -*- |
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# Copyright 2014-2018 by Christopher C. Little. |
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# This file is part of Abydos. |
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# |
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# Abydos is free software: you can redistribute it and/or modify |
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# it under the terms of the GNU General Public License as published by |
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# the Free Software Foundation, either version 3 of the License, or |
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# (at your option) any later version. |
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# |
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# Abydos is distributed in the hope that it will be useful, |
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# but WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with Abydos. If not, see <http://www.gnu.org/licenses/>. |
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"""abydos.distance._suffix. |
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Suffix similarity & distance |
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""" |
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from __future__ import ( |
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absolute_import, |
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division, |
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print_function, |
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unicode_literals, |
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) |
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from six.moves import range |
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from ._distance import _Distance |
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__all__ = ['Suffix', 'dist_suffix', 'sim_suffix'] |
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View Code Duplication |
class Suffix(_Distance): |
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"""Suffix similarity and distance.""" |
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def sim(self, src, tar): |
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"""Return the suffix similarity of two strings. |
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Suffix similarity is the ratio of the length of the shorter term that |
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exactly matches the longer term to the length of the shorter term, |
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beginning at the end of both terms. |
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Parameters |
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---------- |
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src : str |
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Source string for comparison |
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tar : str |
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Target string for comparison |
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Returns |
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------- |
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float |
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Suffix similarity |
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Examples |
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-------- |
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>>> cmp = Suffix() |
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>>> cmp.sim('cat', 'hat') |
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0.6666666666666666 |
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>>> cmp.sim('Niall', 'Neil') |
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0.25 |
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>>> cmp.sim('aluminum', 'Catalan') |
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0.0 |
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>>> cmp.sim('ATCG', 'TAGC') |
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0.0 |
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""" |
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if src == tar: |
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return 1.0 |
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if not src or not tar: |
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return 0.0 |
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min_word, max_word = (src, tar) if len(src) < len(tar) else (tar, src) |
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min_len = len(min_word) |
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for i in range(min_len, 0, -1): |
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if min_word[-i:] == max_word[-i:]: |
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return i / min_len |
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return 0.0 |
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def sim_suffix(src, tar): |
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"""Return the suffix similarity of two strings. |
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This is a wrapper for :py:meth:`Suffix.sim`. |
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Parameters |
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---------- |
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src : str |
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Source string for comparison |
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tar : str |
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Target string for comparison |
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Returns |
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------- |
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float |
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Suffix similarity |
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Examples |
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-------- |
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>>> sim_suffix('cat', 'hat') |
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0.6666666666666666 |
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>>> sim_suffix('Niall', 'Neil') |
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0.25 |
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>>> sim_suffix('aluminum', 'Catalan') |
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0.0 |
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>>> sim_suffix('ATCG', 'TAGC') |
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0.0 |
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""" |
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return Suffix().sim(src, tar) |
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def dist_suffix(src, tar): |
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"""Return the suffix distance between two strings. |
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This is a wrapper for :py:meth:`Suffix.dist`. |
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Parameters |
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---------- |
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src : str |
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Source string for comparison |
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tar : str |
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Target string for comparison |
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Returns |
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------- |
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float |
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Suffix distance |
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Examples |
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-------- |
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>>> dist_suffix('cat', 'hat') |
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0.33333333333333337 |
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>>> dist_suffix('Niall', 'Neil') |
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0.75 |
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>>> dist_suffix('aluminum', 'Catalan') |
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1.0 |
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>>> dist_suffix('ATCG', 'TAGC') |
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1.0 |
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""" |
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return Suffix().dist(src, tar) |
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if __name__ == '__main__': |
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import doctest |
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doctest.testmod() |
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