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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.stemmer._clef_german. |
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CLEF German stemmer |
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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 unicodedata import normalize |
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from six import text_type |
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from ._stemmer import _Stemmer |
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__all__ = ['CLEFGerman', 'clef_german'] |
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class CLEFGerman(_Stemmer): |
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"""CLEF German stemmer. |
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The CLEF German stemmer is defined at :cite:`Savoy:2005`. |
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""" |
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_umlauts = dict(zip((ord(_) for _ in 'äöü'), 'aou')) |
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def stem(self, word): |
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"""Return CLEF German stem. |
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Parameters |
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---------- |
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word : str |
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The word to stem |
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Returns |
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------- |
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str |
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Word stem |
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Examples |
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-------- |
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>>> stmr = CLEFGerman() |
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>>> stmr.stem('lesen') |
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'lese' |
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>>> stmr.stem('graues') |
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'grau' |
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>>> stmr.stem('buchstabieren') |
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'buchstabier' |
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""" |
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# lowercase, normalize, and compose |
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word = normalize('NFC', text_type(word.lower())) |
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# remove umlauts |
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word = word.translate(self._umlauts) |
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# remove plurals |
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wlen = len(word) - 1 |
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if wlen > 3: |
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if wlen > 5: |
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if word[-3:] == 'nen': |
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return word[:-3] |
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if wlen > 4: |
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if word[-2:] in {'en', 'se', 'es', 'er'}: |
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return word[:-2] |
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if word[-1] in {'e', 'n', 'r', 's'}: |
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return word[:-1] |
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return word |
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def clef_german(word): |
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"""Return CLEF German stem. |
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This is a wrapper for :py:meth:`CLEFGerman.stem`. |
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Parameters |
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---------- |
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word : str |
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The word to stem |
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Returns |
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------- |
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str |
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Word stem |
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Examples |
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-------- |
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>>> clef_german('lesen') |
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'lese' |
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>>> clef_german('graues') |
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'grau' |
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>>> clef_german('buchstabieren') |
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'buchstabier' |
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""" |
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return CLEFGerman().stem(word) |
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if __name__ == '__main__': |
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import doctest |
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doctest.testmod() |
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