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