abydos.phonetic.es.spanish_metaphone()

Complexity

Conditions

29

Size

Total Lines	150
Code Lines	89

Duplication

Lines	0
Ratio	0 %

Importance

Changes

0

# -*- coding: utf-8 -*-
def spanish_metaphone(word, max_length=6, modified=False):
    """Return the Spanish Metaphone of a word.

    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`.

    :param str word: the word to transform
    :param int max_length: the length of the code returned (defaults to 6)
    :param bool modified: Set to True to use del Pilar Angeles &
        Bailón-Miguel's modified version of the algorithm
    :returns: the Spanish Metaphone code
    :rtype: str

    >>> spanish_metaphone('Perez')
    'PRZ'
    >>> spanish_metaphone('Martinez')
    'MRTNZ'
    >>> spanish_metaphone('Gutierrez')
    'GTRRZ'
    >>> spanish_metaphone('Santiago')
    'SNTG'
    >>> spanish_metaphone('Nicolás')
    'NKLS'
    """
    def _is_vowel(pos):
        """Return True if the character at word[pos] is a vowel."""
        return (pos < len(word) and
                word[pos] in {'A', 'E', 'I', 'O', 'U'})

    word = unicode_normalize('NFC', text_type(word.upper()))

    meta_key = ''
    pos = 0

    # do some replacements for the modified version
    if 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) < 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 modified:
        meta_key = meta_key.replace('S', 'Z')

    return meta_key