67 lines
2.0 KiB
Python
67 lines
2.0 KiB
Python
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# Natural Language Toolkit: Text Trees
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#
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# Copyright (C) 2001-2023 NLTK Project
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# Author: Edward Loper <edloper@gmail.com>
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# Steven Bird <stevenbird1@gmail.com>
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# Peter Ljunglöf <peter.ljunglof@gu.se>
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# Tom Aarsen <>
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# URL: <https://www.nltk.org/>
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# For license information, see LICENSE.TXT
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import re
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from nltk.tree.tree import Tree
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######################################################################
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## Parsing
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######################################################################
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def bracket_parse(s):
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"""
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Use Tree.read(s, remove_empty_top_bracketing=True) instead.
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"""
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raise NameError("Use Tree.read(s, remove_empty_top_bracketing=True) instead.")
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def sinica_parse(s):
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"""
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Parse a Sinica Treebank string and return a tree. Trees are represented as nested brackettings,
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as shown in the following example (X represents a Chinese character):
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S(goal:NP(Head:Nep:XX)|theme:NP(Head:Nhaa:X)|quantity:Dab:X|Head:VL2:X)#0(PERIODCATEGORY)
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:return: A tree corresponding to the string representation.
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:rtype: Tree
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:param s: The string to be converted
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:type s: str
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"""
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tokens = re.split(r"([()| ])", s)
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for i in range(len(tokens)):
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if tokens[i] == "(":
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tokens[i - 1], tokens[i] = (
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tokens[i],
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tokens[i - 1],
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) # pull nonterminal inside parens
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elif ":" in tokens[i]:
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fields = tokens[i].split(":")
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if len(fields) == 2: # non-terminal
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tokens[i] = fields[1]
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else:
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tokens[i] = "(" + fields[-2] + " " + fields[-1] + ")"
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elif tokens[i] == "|":
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tokens[i] = ""
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treebank_string = " ".join(tokens)
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return Tree.fromstring(treebank_string, remove_empty_top_bracketing=True)
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# s = re.sub(r'^#[^\s]*\s', '', s) # remove leading identifier
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# s = re.sub(r'\w+:', '', s) # remove role tags
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# return s
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__all__ = [
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"bracket_parse",
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"sinica_parse",
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]
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