#! python3
# -*- coding: UTF-8 -*-
# This script implements the Double Metaphone algorithm (c) 1998, 1999 by Lawrence Philips
# it was translated to Python from the C source written by Kevin Atkinson (http://aspell.net/metaphone/)
# By Andrew Collins - January 12, 2007 who claims no rights to this work
# http://atomboy.isa-geek.com/plone/Members/acoil/programing/double-metaphone
# Tested with Python 2.4.3
# Updated Feb 14, 2007 - Found a typo in the 'gh' section
# Updated Dec 17, 2007 - Bugs fixed in 'S', 'Z', and 'J' sections. Thanks Chris Leong!
# Updated 2009-03-05 by Matthew Somerville - Various bug fixes against the reference C++ implementation.
"""
>>> dm(u'aubrey')
('APR', '')
>>> dm(u'richard')
('RXRT', 'RKRT')
>>> dm(u'katherine') == dm(u'catherine')
True
>>> dm(u'Bartoš'), dm(u'Bartosz'), dm(u'Bartosch'), dm(u'Bartos')
(('PRT', ''), ('PRTS', 'PRTX'), ('PRTX', ''), ('PRTS', ''))
"""
import unicodedata
def dm (st):
"""dm(string) -> (string, string or '')
returns the double metaphone codes for given string - always a tuple
there are no checks done on the input string, but it should be a single word or name."""
vowels = ['A', 'E', 'I', 'O', 'U', 'Y']
st = ''.join((c for c in unicodedata.normalize('NFD', st) if unicodedata.category(c) != 'Mn'))
st = st.upper() # st is short for string. I usually prefer descriptive over short, but this var is used a lot!
is_slavo_germanic = (st.find('W') > -1 or st.find('K') > -1 or st.find('CZ') > -1 or st.find('WITZ') > -1)
length = len(st)
first = 2
st = '-' * first + st + '------' # so we can index beyond the begining and end of the input string
last = first + length - 1
pos = first # pos is short for position
pri = sec = '' # primary and secondary metaphone codes
# skip these silent letters when at start of word
if st[first:first + 2] in ["GN", "KN", "PN", "WR", "PS"]:
pos += 1
# Initial 'X' is pronounced 'Z' e.g. 'Xavier'
if st[first] == 'X':
pri = sec = 'S' # 'Z' maps to 'S'
pos += 1
# main loop through chars in st
while pos <= last:
#print str(pos) + '\t' + st[pos]
ch = st[pos] # ch is short for character
# nxt (short for next characters in metaphone code) is set to a tuple of the next characters in
# the primary and secondary codes and how many characters to move forward in the string.
# the secondary code letter is given only when it is different than the primary.
# This is just a trick to make the code easier to write and read.
nxt = (None, 1) # default action is to add nothing and move to next char
if ch in vowels:
nxt = (None, 1)
if pos == first: # all init vowels now map to 'A'
nxt = ('A', 1)
elif ch == 'B':
#"-mb", e.g", "dumb", already skipped over... see 'M' below
if st[pos + 1] == 'B':
nxt = ('P', 2)
else:
nxt = ('P', 1)
elif ch == 'C':
# various germanic
if pos > first + 1 and st[pos - 2] not in vowels and st[pos - 1:pos + 2] == 'ACH' and \
st[pos + 2] not in ['I'] and (st[pos + 2] not in ['E'] or st[pos - 2:pos + 4] in ['BACHER', 'MACHER']):
nxt = ('K', 2)
# special case 'CAESAR'
elif pos == first and st[first:first + 6] == 'CAESAR':
nxt = ('S', 2)
elif st[pos:pos + 4] == 'CHIA': # italian 'chianti'
nxt = ('K', 2)
elif st[pos:pos + 2] == 'CH':
# find 'michael'
if pos > first and st[pos:pos + 4] == 'CHAE':
nxt = ('K', 'X', 2)
elif pos == first and (st[pos + 1:pos + 6] in ['HARAC', 'HARIS'] or \
st[pos + 1:pos + 4] in ["HOR", "HYM", "HIA", "HEM"]) and st[first:first + 5] != 'CHORE':
nxt = ('K', 2)
#germanic, greek, or otherwise 'ch' for 'kh' sound
elif st[first:first + 4] in ['VAN ', 'VON '] or st[first:first + 3] == 'SCH' \
or st[pos - 2:pos + 4] in ["ORCHES", "ARCHIT", "ORCHID"] \
or st[pos + 2] in ['T', 'S'] \
or ((st[pos - 1] in ["A", "O", "U", "E"] or pos == first) \
and st[pos + 2] in ["L", "R", "N", "M", "B", "H", "F", "V", "W"]):
nxt = ('K', 2)
else:
if pos > first:
if st[first:first + 2] == 'MC':
nxt = ('K', 2)
else:
nxt = ('X', 'K', 2)
else:
nxt = ('X', 2)
# e.g, 'czerny'
elif st[pos:pos + 2] == 'CZ' and st[pos - 2:pos + 2] != 'WICZ':
nxt = ('S', 'X', 2)
# e.g., 'focaccia'
elif st[pos + 1:pos + 4] == 'CIA':
nxt = ('X', 3)
# double 'C', but not if e.g. 'McClellan'
elif st[pos:pos + 2] == 'CC' and not (pos == (first + 1) and st[first] == 'M'):
#'bellocchio' but not 'bacchus'
if st[pos + 2] in ["I", "E", "H"] and st[pos + 2:pos + 4] != 'HU':
# 'accident', 'accede' 'succeed'
if (pos == (first + 1) and st[first] == 'A') or \
st[pos - 1:pos + 4] in ['UCCEE', 'UCCES']:
nxt = ('KS', 3)
# 'bacci', 'bertucci', other italian
else:
nxt = ('X', 3)
else:
nxt = ('K', 2)
elif st[pos:pos + 2] in ["CK", "CG", "CQ"]:
nxt = ('K', 2)
elif st[pos:pos + 2] in ["CI", "CE", "CY"]:
# italian vs. english
if st[pos:pos + 3] in ["CIO", "CIE", "CIA"]:
nxt = ('S', 'X', 2)
else:
nxt = ('S', 2)
else:
# name sent in 'mac caffrey', 'mac gregor
if st[pos + 1:pos + 3] in [" C", " Q", " G"]:
nxt = ('K', 3)
else:
if st[pos + 1] in ["C", "K", "Q"] and st[pos + 1:pos + 3] not in ["CE", "CI"]:
nxt = ('K', 2)
else: # default for 'C'
nxt = ('K', 1)
elif ch == u'\xc7': # will never get here with st.encode('ascii', 'replace') above
# \xc7 is UTF-8 encoding of Ç
nxt = ('S', 1)
elif ch == 'D':
if st[pos:pos + 2] == 'DG':
if st[pos + 2] in ['I', 'E', 'Y']: # e.g. 'edge'
nxt = ('J', 3)
else:
nxt = ('TK', 2)
elif st[pos:pos + 2] in ['DT', 'DD']:
nxt = ('T', 2)
else:
nxt = ('T', 1)
elif ch == 'F':
if st[pos + 1] == 'F':
nxt = ('F', 2)
else:
nxt = ('F', 1)
elif ch == 'G':
if st[pos + 1] == 'H':
if pos > first and st[pos - 1] not in vowels:
nxt = ('K', 2)
elif pos < (first + 3):
if pos == first: # 'ghislane', ghiradelli
if st[pos + 2] == 'I':
nxt = ('J', 2)
else:
nxt = ('K', 2)
# Parker's rule (with some further refinements) - e.g., 'hugh'
elif (pos > (first + 1) and st[pos - 2] in ['B', 'H', 'D']) \
or (pos > (first + 2) and st[pos - 3] in ['B', 'H', 'D']) \
or (pos > (first + 3) and st[pos - 3] in ['B', 'H']):
nxt = (None, 2)
else:
# e.g., 'laugh', 'McLaughlin', 'cough', 'gough', 'rough', 'tough'
if pos > (first + 2) and st[pos - 1] == 'U' \
and st[pos - 3] in ["C", "G", "L", "R", "T"]:
nxt = ('F', 2)
else:
if pos > first and st[pos - 1] != 'I':
nxt = ('K', 2)
elif st[pos + 1] == 'N':
if pos == (first + 1) and st[first] in vowels and not is_slavo_germanic:
nxt = ('KN', 'N', 2)
else:
# not e.g. 'cagney'
if st[pos + 2:pos + 4] != 'EY' and st[pos + 1] != 'Y' and not is_slavo_germanic:
nxt = ('N', 'KN', 2)
else:
nxt = ('KN', 2)
# 'tagliaro'
elif st[pos + 1:pos + 3] == 'LI' and not is_slavo_germanic:
nxt = ('KL', 'L', 2)
# -ges-,-gep-,-gel-, -gie- at beginning
elif pos == first and (st[pos + 1] == 'Y' \
or st[pos + 1:pos + 3] in ["ES", "EP", "EB", "EL", "EY", "IB", "IL", "IN", "IE", "EI", "ER"]):
nxt = ('K', 'J', 2)
# -ger-, -gy-
elif (st[pos + 1:pos + 3] == 'ER' or st[pos + 1] == 'Y') \
and st[first:first + 6] not in ["DANGER", "RANGER", "MANGER"] \
and st[pos - 1] not in ['E', 'I'] and st[pos - 1:pos + 2] not in ['RGY', 'OGY']:
nxt = ('K', 'J', 2)
# italian e.g, 'biaggi'
elif st[pos + 1] in ['E', 'I', 'Y'] or st[pos - 1:pos + 3] in ["AGGI", "OGGI"]:
# obvious germanic
if st[first:first + 4] in ['VON ', 'VAN '] or st[first:first + 3] == 'SCH' \
or st[pos + 1:pos + 3] == 'ET':
nxt = ('K', 2)
else:
# always soft if french ending
if st[pos + 1:pos + 5] == 'IER ':
nxt = ('J', 2)
else:
nxt = ('J', 'K', 2)
elif st[pos + 1] == 'G':
nxt = ('K', 2)
else:
nxt = ('K', 1)
elif ch == 'H':
# only keep if first & before vowel or btw. 2 vowels
if (pos == first or st[pos - 1] in vowels) and st[pos + 1] in vowels:
nxt = ('H', 2)
else: # (also takes care of 'HH')
nxt = (None, 1)
elif ch == 'J':
# obvious spanish, 'jose', 'san jacinto'
if st[pos:pos + 4] == 'JOSE' or st[first:first + 4] == 'SAN ':
if (pos == first and st[pos + 4] == ' ') or st[first:first + 4] == 'SAN ':
nxt = ('H', )
else:
nxt = ('J', 'H')
elif pos == first and st[pos:pos + 4] != 'JOSE':
nxt = ('J', 'A') # Yankelovich/Jankelowicz
else:
# spanish pron. of e.g. 'bajador'
if st[pos - 1] in vowels and not is_slavo_germanic \
and st[pos + 1] in ['A', 'O']:
nxt = ('J', 'H')
else:
if pos == last:
nxt = ('J', ' ')
else:
if st[pos + 1] not in ["L", "T", "K", "S", "N", "M", "B", "Z"] \
and st[pos - 1] not in ["S", "K", "L"]:
nxt = ('J', )
else:
nxt = (None, )
if st[pos + 1] == 'J':
nxt = nxt + (2, )
else:
nxt = nxt + (1, )
elif ch == 'K':
if st[pos + 1] == 'K':
nxt = ('K', 2)
else:
nxt = ('K', 1)
elif ch == 'L':
if st[pos + 1] == 'L':
# spanish e.g. 'cabrillo', 'gallegos'
if (pos == (last - 2) and st[pos - 1:pos + 3] in ["ILLO", "ILLA", "ALLE"]) \
or ((st[last - 1:last + 1] in ["AS", "OS"] or st[last] in ["A", "O"]) \
and st[pos - 1:pos + 3] == 'ALLE'):
nxt = ('L', ' ', 2)
else:
nxt = ('L', 2)
else:
nxt = ('L', 1)
elif ch == 'M':
if (st[pos + 1:pos + 4] == 'UMB' \
and (pos + 1 == last or st[pos + 2:pos + 4] == 'ER')) \
or st[pos + 1] == 'M':
nxt = ('M', 2)
else:
nxt = ('M', 1)
elif ch == 'N':
if st[pos + 1] == 'N':
nxt = ('N', 2)
else:
nxt = ('N', 1)
elif ch == u'\xd1': # UTF-8 encoding of ﾄ
nxt = ('N', 1)
elif ch == 'P':
if st[pos + 1] == 'H':
nxt = ('F', 2)
elif st[pos + 1] in ['P', 'B']: # also account for "campbell", "raspberry"
nxt = ('P', 2)
else:
nxt = ('P', 1)
elif ch == 'Q':
if st[pos + 1] == 'Q':
nxt = ('K', 2)
else:
nxt = ('K', 1)
elif ch == 'R':
# french e.g. 'rogier', but exclude 'hochmeier'
if pos == last and not is_slavo_germanic \
and st[pos - 2:pos] == 'IE' and st[pos - 4:pos - 2] not in ['ME', 'MA']:
nxt = ('', 'R')
else:
nxt = ('R', )
if st[pos + 1] == 'R':
nxt = nxt + (2, )
else:
nxt = nxt + (1, )
elif ch == 'S':
# special cases 'island', 'isle', 'carlisle', 'carlysle'
if st[pos - 1:pos + 2] in ['ISL', 'YSL']:
nxt = (None, 1)
# special case 'sugar-'
elif pos == first and st[first:first + 5] == 'SUGAR':
nxt = ('X', 'S', 1)
elif st[pos:pos + 2] == 'SH':
# germanic
if st[pos + 1:pos + 5] in ["HEIM", "HOEK", "HOLM", "HOLZ"]:
nxt = ('S', 2)
else:
nxt = ('X', 2)
# italian & armenian
elif st[pos:pos + 3] in ["SIO", "SIA"] or st[pos:pos + 4] == 'SIAN':
if not is_slavo_germanic:
nxt = ('S', 'X', 3)
else:
nxt = ('S', 3)
# german & anglicisations, e.g. 'smith' match 'schmidt', 'snider' match 'schneider'
# also, -sz- in slavic language altho in hungarian it is pronounced 's'
elif (pos == first and st[pos + 1] in ["M", "N", "L", "W"]) or st[pos + 1] == 'Z':
nxt = ('S', 'X')
if st[pos + 1] == 'Z':
nxt = nxt + (2, )
else:
nxt = nxt + (1, )
elif st[pos:pos + 2] == 'SC':
# Schlesinger's rule
if st[pos + 2] == 'H':
# dutch origin, e.g. 'school', 'schooner'
if st[pos + 3:pos + 5] in ["OO", "ER", "EN", "UY", "ED", "EM"]:
# 'schermerhorn', 'schenker'
if st[pos + 3:pos + 5] in ['ER', 'EN']:
nxt = ('X', 'SK', 3)
else:
nxt = ('SK', 3)
else:
if pos == first and st[first + 3] not in vowels and st[first + 3] != 'W':
nxt = ('X', 'S', 3)
else:
nxt = ('X', 3)
elif st[pos + 2] in ['I', 'E', 'Y']:
nxt = ('S', 3)
else:
nxt = ('SK', 3)
# french e.g. 'resnais', 'artois'
elif pos == last and st[pos - 2:pos] in ['AI', 'OI']:
nxt = ('', 'S', 1)
else:
nxt = ('S', )
if st[pos + 1] in ['S', 'Z']:
nxt = nxt + (2, )
else:
nxt = nxt + (1, )
elif ch == 'T':
if st[pos:pos + 4] == 'TION':
nxt = ('X', 3)
elif st[pos:pos + 3] in ['TIA', 'TCH']:
nxt = ('X', 3)
elif st[pos:pos + 2] == 'TH' or st[pos:pos + 3] == 'TTH':
# special case 'thomas', 'thames' or germanic
if st[pos + 2:pos + 4] in ['OM', 'AM'] or st[first:first + 4] in ['VON ', 'VAN '] \
or st[first:first + 3] == 'SCH':
nxt = ('T', 2)
else:
nxt = ('0', 'T', 2)
elif st[pos + 1] in ['T', 'D']:
nxt = ('T', 2)
else:
nxt = ('T', 1)
elif ch == 'V':
if st[pos + 1] == 'V':
nxt = ('F', 2)
else:
nxt = ('F', 1)
elif ch == 'W':
# can also be in middle of word
if st[pos:pos + 2] == 'WR':
nxt = ('R', 2)
elif pos == first and (st[pos + 1] in vowels or st[pos:pos + 2] == 'WH'):
# Wasserman should match Vasserman
if st[pos + 1] in vowels:
nxt = ('A', 'F', 1)
else:
nxt = ('A', 1)
# Arnow should match Arnoff
elif (pos == last and st[pos - 1] in vowels) \
or st[pos - 1:pos + 4] in ["EWSKI", "EWSKY", "OWSKI", "OWSKY"] \
or st[first:first + 3] == 'SCH':
nxt = ('', 'F', 1)
# polish e.g. 'filipowicz'
elif st[pos:pos + 4] in ["WICZ", "WITZ"]:
nxt = ('TS', 'FX', 4)
else: # default is to skip it
nxt = (None, 1)
elif ch == 'X':
# french e.g. breaux
nxt = (None, )
if not(pos == last and (st[pos - 3:pos] in ["IAU", "EAU"] \
or st[pos - 2:pos] in ['AU', 'OU'])):
nxt = ('KS', )
if st[pos + 1] in ['C', 'X']:
nxt = nxt + (2, )
else:
nxt = nxt + (1, )
elif ch == 'Z':
# chinese pinyin e.g. 'zhao'
if st[pos + 1] == 'H':
nxt = ('J', )
elif st[pos + 1:pos + 3] in ["ZO", "ZI", "ZA"] \
or (is_slavo_germanic and pos > first and st[pos - 1] != 'T'):
nxt = ('S', 'TS')
else:
nxt = ('S', )
if st[pos + 1] == 'Z' or st[pos + 1] == 'H':
nxt = nxt + (2, )
else:
nxt = nxt + (1, )
# ----------------------------------
# --- end checking letters------
# ----------------------------------
#print str(nxt)
if len(nxt) == 2:
if nxt[0]:
pri += nxt[0]
sec += nxt[0]
pos += nxt[1]
elif len(nxt) == 3:
if nxt[0]:
pri += nxt[0]
if nxt[1]:
sec += nxt[1]
pos += nxt[2]
if pri == sec:
return (pri, '')
else:
return (pri, sec)
if __name__ == '__main__':
import doctest
doctest.testmod()