abydos/phonetic/_koelner.py
# 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.phonetic._koelner.
Kölner Phonetik
"""
from typing import Set
from unicodedata import normalize as unicode_normalize
from ._phonetic import _Phonetic
__all__ = [
'Koelner',
]
class Koelner(_Phonetic):
"""Kölner Phonetik.
Based on the algorithm defined by :cite:`Postel:1969`.
.. versionadded:: 0.3.6
"""
_uc_v_set = set('AEIOUJY')
_num_trans = dict(zip((ord(_) for _ in '012345678'), 'APTFKLNRS'))
_num_set = set('012345678')
def encode(self, word: str) -> str:
"""Return the Kölner Phonetik (numeric output) code for a word.
While the output code is numeric, it is still a str because 0s can lead
the code.
Parameters
----------
word : str
The word to transform
Returns
-------
str
The Kölner Phonetik value as a numeric string
Example
-------
>>> pe = Koelner()
>>> pe.encode('Christopher')
'478237'
>>> pe.encode('Niall')
'65'
>>> pe.encode('Smith')
'862'
>>> pe.encode('Schmidt')
'862'
>>> pe.encode('Müller')
'657'
>>> pe.encode('Zimmermann')
'86766'
.. versionadded:: 0.1.0
.. versionchanged:: 0.3.6
Encapsulated in class
"""
def _after(word: str, pos: int, letters: Set[str]) -> bool:
"""Return True if word[pos] follows one of the supplied letters.
Parameters
----------
word : str
The word to check
pos : int
Position within word to check
letters : {str}
Letters to confirm precede word[pos]
Returns
-------
bool
True if word[pos] follows a value in letters
.. versionadded:: 0.1.0
"""
return pos > 0 and word[pos - 1] in letters
def _before(word: str, pos: int, letters: Set[str]) -> bool:
"""Return True if word[pos] precedes one of the supplied letters.
Parameters
----------
word : str
The word to check
pos : int
Position within word to check
letters : {str}
Letters to confirm follow word[pos]
Returns
-------
bool
True if word[pos] precedes a value in letters
.. versionadded:: 0.1.0
"""
return pos + 1 < len(word) and word[pos + 1] in letters
sdx = ''
word = unicode_normalize('NFKD', word.upper())
word = word.replace('Ä', 'AE')
word = word.replace('Ö', 'OE')
word = word.replace('Ü', 'UE')
word = ''.join(c for c in word if c in self._uc_set)
# Nothing to convert, return base case
if not word:
return sdx
for i in range(len(word)):
if word[i] in self._uc_v_set:
sdx += '0'
elif word[i] == 'B':
sdx += '1'
elif word[i] == 'P':
if _before(word, i, {'H'}):
sdx += '3'
else:
sdx += '1'
elif word[i] in {'D', 'T'}:
if _before(word, i, {'C', 'S', 'Z'}):
sdx += '8'
else:
sdx += '2'
elif word[i] in {'F', 'V', 'W'}:
sdx += '3'
elif word[i] in {'G', 'K', 'Q'}:
sdx += '4'
elif word[i] == 'C':
if _after(word, i, {'S', 'Z'}):
sdx += '8'
elif i == 0:
if _before(
word, i, {'A', 'H', 'K', 'L', 'O', 'Q', 'R', 'U', 'X'}
):
sdx += '4'
else:
sdx += '8'
elif _before(word, i, {'A', 'H', 'K', 'O', 'Q', 'U', 'X'}):
sdx += '4'
else:
sdx += '8'
elif word[i] == 'X':
if _after(word, i, {'C', 'K', 'Q'}):
sdx += '8'
else:
sdx += '48'
elif word[i] == 'L':
sdx += '5'
elif word[i] in {'M', 'N'}:
sdx += '6'
elif word[i] == 'R':
sdx += '7'
elif word[i] in {'S', 'Z'}:
sdx += '8'
sdx = self._delete_consecutive_repeats(sdx)
if sdx:
sdx = sdx[:1] + sdx[1:].replace('0', '')
return sdx
def encode_alpha(self, word: str) -> str:
"""Return the Kölner Phonetik (alphabetic output) code for a word.
Parameters
----------
word : str
The word to transform
Returns
-------
str
The Kölner Phonetik value as an alphabetic string
Examples
--------
>>> pe = Koelner()
>>> pe.encode_alpha('Smith')
'SNT'
>>> pe.encode_alpha('Schmidt')
'SNT'
>>> pe.encode_alpha('Müller')
'NLR'
>>> pe.encode_alpha('Zimmermann')
'SNRNN'
.. versionadded:: 0.1.0
.. versionchanged:: 0.3.6
Encapsulated in class
"""
num = ''.join(c for c in self.encode(word) if c in self._num_set)
return num.translate(self._num_trans)
if __name__ == '__main__':
import doctest
doctest.testmod()