Source code for nltk.tokenize.toktok

# -*- coding: utf-8 -*-
# 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: <http://nltk.sourceforge.net>
# 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(u"\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(u"([–—])"), r" \1 " # Replace problematic character with numeric character reference. AMPERCENT = re.compile("& "), "&amp; " TAB = re.compile("\t"), " &#9; " PIPE = re.compile(r"\|"), " &#124; " # 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 http://perldoc.perl.org/perluniprops.html OPEN_PUNCT = str( u"([{\u0f3a\u0f3c\u169b\u201a\u201e\u2045\u207d" u"\u208d\u2329\u2768\u276a\u276c\u276e\u2770\u2772" u"\u2774\u27c5\u27e6\u27e8\u27ea\u27ec\u27ee\u2983" u"\u2985\u2987\u2989\u298b\u298d\u298f\u2991\u2993" u"\u2995\u2997\u29d8\u29da\u29fc\u2e22\u2e24\u2e26" u"\u2e28\u3008\u300a\u300c\u300e\u3010\u3014\u3016" u"\u3018\u301a\u301d\ufd3e\ufe17\ufe35\ufe37\ufe39" u"\ufe3b\ufe3d\ufe3f\ufe41\ufe43\ufe47\ufe59\ufe5b" u"\ufe5d\uff08\uff3b\uff5b\uff5f\uff62" ) # This is the \p{Close_Punctuation} from Perl's perluniprops CLOSE_PUNCT = str( u")]}\u0f3b\u0f3d\u169c\u2046\u207e\u208e\u232a" u"\u2769\u276b\u276d\u276f\u2771\u2773\u2775\u27c6" u"\u27e7\u27e9\u27eb\u27ed\u27ef\u2984\u2986\u2988" u"\u298a\u298c\u298e\u2990\u2992\u2994\u2996\u2998" u"\u29d9\u29db\u29fd\u2e23\u2e25\u2e27\u2e29\u3009" u"\u300b\u300d\u300f\u3011\u3015\u3017\u3019\u301b" u"\u301e\u301f\ufd3f\ufe18\ufe36\ufe38\ufe3a\ufe3c" u"\ufe3e\ufe40\ufe42\ufe44\ufe48\ufe5a\ufe5c\ufe5e" u"\uff09\uff3d\uff5d\uff60\uff63" ) # This is the \p{Close_Punctuation} from Perl's perluniprops CURRENCY_SYM = str( u"$\xa2\xa3\xa4\xa5\u058f\u060b\u09f2\u09f3\u09fb" u"\u0af1\u0bf9\u0e3f\u17db\u20a0\u20a1\u20a2\u20a3" u"\u20a4\u20a5\u20a6\u20a7\u20a8\u20a9\u20aa\u20ab" u"\u20ac\u20ad\u20ae\u20af\u20b0\u20b1\u20b2\u20b3" u"\u20b4\u20b5\u20b6\u20b7\u20b8\u20b9\u20ba\ua838" u"\ufdfc\ufe69\uff04\uffe0\uffe1\uffe5\uffe6" ) # Pad spaces after opening punctuations. OPEN_PUNCT_RE = re.compile(u"([{}])".format(OPEN_PUNCT)), r"\1 " # Pad spaces before closing punctuations. CLOSE_PUNCT_RE = re.compile(u"([{}])".format(CLOSE_PUNCT)), r"\1 " # Pad spaces after currency symbols. CURRENCY_SYM_RE = re.compile(u"([{}])".format(CURRENCY_SYM)), r"\1 " # Use for tokenizing URL-unfriendly characters: [:/?#] URL_FOE_1 = re.compile(r":(?!//)"), r" : " # in perl s{:(?!//)}{ : }g; URL_FOE_2 = re.compile(r"\?(?!\S)"), r" ? " # in perl s{\?(?!\S)}{ ? }g; # in perl: m{://} or m{\S+\.\S+/\S+} or s{/}{ / }g; URL_FOE_3 = re.compile(r"(:\/\/)[\S+\.\S+\/\S+][\/]"), " / " URL_FOE_4 = re.compile(r" /"), r" / " # s{ /}{ / }g; # Left/Right strip, i.e. remove heading/trailing spaces. # These strip regexes should NOT be used, # instead use str.lstrip(), str.rstrip() or str.strip() # (They are kept for reference purposes to the original toktok.pl code) LSTRIP = re.compile(r"^ +"), "" RSTRIP = re.compile(r"\s+$"), "\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, subsitution in self.TOKTOK_REGEXES: text = regexp.sub(subsitution, 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()