abydos/phonetic/_spanish_metaphone.py
# Copyright 2018-2020 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._spanish_metaphone.
Spanish Metaphone
"""
from unicodedata import normalize as unicode_normalize
from ._phonetic import _Phonetic
__all__ = ['SpanishMetaphone']
class SpanishMetaphone(_Phonetic):
"""Spanish Metaphone.
This is a quick rewrite of the Spanish Metaphone Algorithm, as presented at
https://github.com/amsqr/Spanish-Metaphone and discussed in
:cite:`Mosquera:2012`.
Modified version based on :cite:`delPilarAngeles:2016`.
.. versionadded:: 0.3.6
"""
def __init__(self, max_length: int = 6, modified: bool = False) -> None:
"""Initialize AlphaSIS instance.
Parameters
----------
max_length : int
The length of the code returned (defaults to 6)
modified : bool
Set to True to use del Pilar Angeles & Bailón-Miguel's modified
version of the algorithm
.. versionadded:: 0.4.0
"""
self._max_length = max_length
self._modified = modified
def encode(self, word: str) -> str:
"""Return the Spanish Metaphone of a word.
Parameters
----------
word : str
The word to transform
Returns
-------
str
The Spanish Metaphone code
Examples
--------
>>> pe = SpanishMetaphone()
>>> pe.encode('Perez')
'PRZ'
>>> pe.encode('Martinez')
'MRTNZ'
>>> pe.encode('Gutierrez')
'GTRRZ'
>>> pe.encode('Santiago')
'SNTG'
>>> pe.encode('Nicolás')
'NKLS'
.. versionadded:: 0.3.0
.. versionchanged:: 0.3.6
Encapsulated in class
"""
def _is_vowel(pos: int) -> bool:
"""Return True if the character at word[pos] is a vowel.
Parameters
----------
pos : int
Position to check for a vowel
Returns
-------
bool
True if word[pos] is a vowel
.. versionadded:: 0.3.0
"""
return pos < len(word) and word[pos] in {'A', 'E', 'I', 'O', 'U'}
word = unicode_normalize('NFC', word.upper())
meta_key = ''
pos = 0
# do some replacements for the modified version
if self._modified:
word = word.replace('MB', 'NB')
word = word.replace('MP', 'NP')
word = word.replace('BS', 'S')
if word[:2] == 'PS':
word = word[1:]
# simple replacements
word = word.replace('Á', 'A')
word = word.replace('CH', 'X')
word = word.replace('Ç', 'S')
word = word.replace('É', 'E')
word = word.replace('Í', 'I')
word = word.replace('Ó', 'O')
word = word.replace('Ú', 'U')
word = word.replace('Ñ', 'NY')
word = word.replace('GÜ', 'W')
word = word.replace('Ü', 'U')
word = word.replace('B', 'V')
word = word.replace('LL', 'Y')
while len(meta_key) < self._max_length:
if pos >= len(word):
break
# get the next character
current_char = word[pos]
# if a vowel in pos 0, add to key
if _is_vowel(pos) and pos == 0:
meta_key += current_char
pos += 1
# otherwise, do consonant rules
else:
# simple consonants (unmutated)
if current_char in {
'D',
'F',
'J',
'K',
'M',
'N',
'P',
'T',
'V',
'L',
'Y',
}:
meta_key += current_char
# skip doubled consonants
if word[pos + 1 : pos + 2] == current_char:
pos += 2
else:
pos += 1
else:
if current_char == 'C':
# special case 'acción', 'reacción',etc.
if word[pos + 1 : pos + 2] == 'C':
meta_key += 'X'
pos += 2
# special case 'cesar', 'cien', 'cid', 'conciencia'
elif word[pos + 1 : pos + 2] in {'E', 'I'}:
meta_key += 'Z'
pos += 2
# base case
else:
meta_key += 'K'
pos += 1
elif current_char == 'G':
# special case 'gente', 'ecologia',etc
if word[pos + 1 : pos + 2] in {'E', 'I'}:
meta_key += 'J'
pos += 2
# base case
else:
meta_key += 'G'
pos += 1
elif current_char == 'H':
# since the letter 'H' is silent in Spanish,
# set the meta key to the vowel after the letter 'H'
if _is_vowel(pos + 1):
meta_key += word[pos + 1]
pos += 2
else:
meta_key += 'H'
pos += 1
elif current_char == 'Q':
if word[pos + 1 : pos + 2] == 'U':
pos += 2
else:
pos += 1
meta_key += 'K'
elif current_char == 'W':
meta_key += 'U'
pos += 1
elif current_char == 'R':
meta_key += 'R'
pos += 1
elif current_char == 'S':
if not _is_vowel(pos + 1) and pos == 0:
meta_key += 'ES'
pos += 1
else:
meta_key += 'S'
pos += 1
elif current_char == 'Z':
meta_key += 'Z'
pos += 1
elif current_char == 'X':
if (
len(word) > 1
and pos == 0
and not _is_vowel(pos + 1)
):
meta_key += 'EX'
pos += 1
else:
meta_key += 'X'
pos += 1
else:
pos += 1
# Final change from S to Z in modified version
if self._modified:
meta_key = meta_key.replace('S', 'Z')
return meta_key
if __name__ == '__main__':
import doctest
doctest.testmod()