# Natural Language Toolkit: Python port of the tok-tok.pl tokenizer.
#
# Copyright (C) 2001-2015 NLTK Project
# Author: Jon Dehdari
# Contributors: Liling Tan, Selcuk Ayguney, ikegami, Martijn Pieters
#
# URL: <https://www.nltk.org>
# For license information, see LICENSE.TXT
"""
The tok-tok tokenizer is a simple, general tokenizer, where the input has one
sentence per line; thus only final period is tokenized.
Tok-tok has been tested on, and gives reasonably good results for English,
Persian, Russian, Czech, French, German, Vietnamese, Tajik, and a few others.
The input should be in UTF-8 encoding.
Reference:
Jon Dehdari. 2014. A Neurophysiologically-Inspired Statistical Language
Model (Doctoral dissertation). Columbus, OH, USA: The Ohio State University.
"""
import re
from nltk.tokenize.api import TokenizerI
[docs]class ToktokTokenizer(TokenizerI):
"""
This is a Python port of the tok-tok.pl from
https://github.com/jonsafari/tok-tok/blob/master/tok-tok.pl
>>> toktok = ToktokTokenizer()
>>> text = u'Is 9.5 or 525,600 my favorite number?'
>>> print(toktok.tokenize(text, return_str=True))
Is 9.5 or 525,600 my favorite number ?
>>> text = u'The https://github.com/jonsafari/tok-tok/blob/master/tok-tok.pl is a website with/and/or slashes and sort of weird : things'
>>> print(toktok.tokenize(text, return_str=True))
The https://github.com/jonsafari/tok-tok/blob/master/tok-tok.pl is a website with/and/or slashes and sort of weird : things
>>> text = u'\xa1This, is a sentence with weird\xbb symbols\u2026 appearing everywhere\xbf'
>>> expected = u'\xa1 This , is a sentence with weird \xbb symbols \u2026 appearing everywhere \xbf'
>>> assert toktok.tokenize(text, return_str=True) == expected
>>> toktok.tokenize(text) == [u'\xa1', u'This', u',', u'is', u'a', u'sentence', u'with', u'weird', u'\xbb', u'symbols', u'\u2026', u'appearing', u'everywhere', u'\xbf']
True
"""
# Replace non-breaking spaces with normal spaces.
NON_BREAKING = re.compile("\u00A0"), " "
# Pad some funky punctuation.
FUNKY_PUNCT_1 = re.compile(r'([،;؛¿!"\])}»›”؟¡%٪°±©®।॥…])'), r" \1 "
# Pad more funky punctuation.
FUNKY_PUNCT_2 = re.compile(r"([({\[“‘„‚«‹「『])"), r" \1 "
# Pad En dash and em dash
EN_EM_DASHES = re.compile("([–—])"), r" \1 "
# Replace problematic character with numeric character reference.
AMPERCENT = re.compile("& "), "& "
TAB = re.compile("\t"), " 	 "
PIPE = re.compile(r"\|"), " | "
# Pad numbers with commas to keep them from further tokenization.
COMMA_IN_NUM = re.compile(r"(?<!,)([,،])(?![,\d])"), r" \1 "
# Just pad problematic (often neurotic) hyphen/single quote, etc.
PROB_SINGLE_QUOTES = re.compile(r"(['’`])"), r" \1 "
# Group ` ` stupid quotes ' ' into a single token.
STUPID_QUOTES_1 = re.compile(r" ` ` "), r" `` "
STUPID_QUOTES_2 = re.compile(r" ' ' "), r" '' "
# Don't tokenize period unless it ends the line and that it isn't
# preceded by another period, e.g.
# "something ..." -> "something ..."
# "something." -> "something ."
FINAL_PERIOD_1 = re.compile(r"(?<!\.)\.$"), r" ."
# Don't tokenize period unless it ends the line eg.
# " ... stuff." -> "... stuff ."
FINAL_PERIOD_2 = re.compile(r"""(?<!\.)\.\s*(["'’»›”]) *$"""), r" . \1"
# Treat continuous commas as fake German,Czech, etc.: „
MULTI_COMMAS = re.compile(r"(,{2,})"), r" \1 "
# Treat continuous dashes as fake en-dash, etc.
MULTI_DASHES = re.compile(r"(-{2,})"), r" \1 "
# Treat multiple periods as a thing (eg. ellipsis)
MULTI_DOTS = re.compile(r"(\.{2,})"), r" \1 "
# This is the \p{Open_Punctuation} from Perl's perluniprops
# see https://perldoc.perl.org/perluniprops.html
OPEN_PUNCT = str(
"([{\u0f3a\u0f3c\u169b\u201a\u201e\u2045\u207d"
"\u208d\u2329\u2768\u276a\u276c\u276e\u2770\u2772"
"\u2774\u27c5\u27e6\u27e8\u27ea\u27ec\u27ee\u2983"
"\u2985\u2987\u2989\u298b\u298d\u298f\u2991\u2993"
"\u2995\u2997\u29d8\u29da\u29fc\u2e22\u2e24\u2e26"
"\u2e28\u3008\u300a\u300c\u300e\u3010\u3014\u3016"
"\u3018\u301a\u301d\ufd3e\ufe17\ufe35\ufe37\ufe39"
"\ufe3b\ufe3d\ufe3f\ufe41\ufe43\ufe47\ufe59\ufe5b"
"\ufe5d\uff08\uff3b\uff5b\uff5f\uff62"
)
# This is the \p{Close_Punctuation} from Perl's perluniprops
CLOSE_PUNCT = str(
")]}\u0f3b\u0f3d\u169c\u2046\u207e\u208e\u232a"
"\u2769\u276b\u276d\u276f\u2771\u2773\u2775\u27c6"
"\u27e7\u27e9\u27eb\u27ed\u27ef\u2984\u2986\u2988"
"\u298a\u298c\u298e\u2990\u2992\u2994\u2996\u2998"
"\u29d9\u29db\u29fd\u2e23\u2e25\u2e27\u2e29\u3009"
"\u300b\u300d\u300f\u3011\u3015\u3017\u3019\u301b"
"\u301e\u301f\ufd3f\ufe18\ufe36\ufe38\ufe3a\ufe3c"
"\ufe3e\ufe40\ufe42\ufe44\ufe48\ufe5a\ufe5c\ufe5e"
"\uff09\uff3d\uff5d\uff60\uff63"
)
# This is the \p{Close_Punctuation} from Perl's perluniprops
CURRENCY_SYM = str(
"$\xa2\xa3\xa4\xa5\u058f\u060b\u09f2\u09f3\u09fb"
"\u0af1\u0bf9\u0e3f\u17db\u20a0\u20a1\u20a2\u20a3"
"\u20a4\u20a5\u20a6\u20a7\u20a8\u20a9\u20aa\u20ab"
"\u20ac\u20ad\u20ae\u20af\u20b0\u20b1\u20b2\u20b3"
"\u20b4\u20b5\u20b6\u20b7\u20b8\u20b9\u20ba\ua838"
"\ufdfc\ufe69\uff04\uffe0\uffe1\uffe5\uffe6"
)
# Pad spaces after opening punctuations.
OPEN_PUNCT_RE = re.compile(f"([{OPEN_PUNCT}])"), r"\1 "
# Pad spaces before closing punctuations.
CLOSE_PUNCT_RE = re.compile(f"([{CLOSE_PUNCT}])"), r"\1 "
# Pad spaces after currency symbols.
CURRENCY_SYM_RE = re.compile(f"([{CURRENCY_SYM}])"), r"\1 "
# Use for tokenizing URL-unfriendly characters: [:/?#]
URL_FOE_1 = re.compile(r":(?!//)"), r" : " # in perl s{:(?!//)}{ : }g;
URL_FOE_2 = re.compile(r"\?(?!\S)"), r" ? " # in perl s{\?(?!\S)}{ ? }g;
# in perl: m{://} or m{\S+\.\S+/\S+} or s{/}{ / }g;
URL_FOE_3 = re.compile(r"(:\/\/)[\S+\.\S+\/\S+][\/]"), " / "
URL_FOE_4 = re.compile(r" /"), r" / " # s{ /}{ / }g;
# Left/Right strip, i.e. remove heading/trailing spaces.
# These strip regexes should NOT be used,
# instead use str.lstrip(), str.rstrip() or str.strip()
# (They are kept for reference purposes to the original toktok.pl code)
LSTRIP = re.compile(r"^ +"), ""
RSTRIP = re.compile(r"\s+$"), "\n"
# Merge multiple spaces.
ONE_SPACE = re.compile(r" {2,}"), " "
TOKTOK_REGEXES = [
NON_BREAKING,
FUNKY_PUNCT_1,
URL_FOE_1,
URL_FOE_2,
URL_FOE_3,
URL_FOE_4,
AMPERCENT,
TAB,
PIPE,
OPEN_PUNCT_RE,
CLOSE_PUNCT_RE,
MULTI_COMMAS,
COMMA_IN_NUM,
FINAL_PERIOD_2,
PROB_SINGLE_QUOTES,
STUPID_QUOTES_1,
STUPID_QUOTES_2,
CURRENCY_SYM_RE,
EN_EM_DASHES,
MULTI_DASHES,
MULTI_DOTS,
FINAL_PERIOD_1,
FINAL_PERIOD_2,
ONE_SPACE,
]
[docs] def tokenize(self, text, return_str=False):
text = str(text) # Converts input string into unicode.
for regexp, substitution in self.TOKTOK_REGEXES:
text = regexp.sub(substitution, text)
# Finally, strips heading and trailing spaces
# and converts output string into unicode.
text = str(text.strip())
return text if return_str else text.split()