116 lines
3.7 KiB
Python
116 lines
3.7 KiB
Python
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# Natural Language Toolkit: Interface to the Stanford Tokenizer
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#
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# Copyright (C) 2001-2023 NLTK Project
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# Author: Steven Xu <xxu@student.unimelb.edu.au>
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#
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# URL: <https://www.nltk.org/>
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# For license information, see LICENSE.TXT
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import json
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import os
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import tempfile
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import warnings
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from subprocess import PIPE
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from nltk.internals import _java_options, config_java, find_jar, java
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from nltk.parse.corenlp import CoreNLPParser
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from nltk.tokenize.api import TokenizerI
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_stanford_url = "https://nlp.stanford.edu/software/tokenizer.shtml"
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class StanfordTokenizer(TokenizerI):
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r"""
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Interface to the Stanford Tokenizer
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>>> from nltk.tokenize.stanford import StanfordTokenizer
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>>> s = "Good muffins cost $3.88\nin New York. Please buy me\ntwo of them.\nThanks."
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>>> StanfordTokenizer().tokenize(s) # doctest: +SKIP
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['Good', 'muffins', 'cost', '$', '3.88', 'in', 'New', 'York', '.', 'Please', 'buy', 'me', 'two', 'of', 'them', '.', 'Thanks', '.']
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>>> s = "The colour of the wall is blue."
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>>> StanfordTokenizer(options={"americanize": True}).tokenize(s) # doctest: +SKIP
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['The', 'color', 'of', 'the', 'wall', 'is', 'blue', '.']
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"""
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_JAR = "stanford-postagger.jar"
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def __init__(
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self,
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path_to_jar=None,
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encoding="utf8",
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options=None,
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verbose=False,
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java_options="-mx1000m",
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):
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# Raise deprecation warning.
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warnings.warn(
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str(
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"\nThe StanfordTokenizer will "
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"be deprecated in version 3.2.5.\n"
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"Please use \033[91mnltk.parse.corenlp.CoreNLPParser\033[0m instead.'"
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),
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DeprecationWarning,
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stacklevel=2,
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)
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self._stanford_jar = find_jar(
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self._JAR,
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path_to_jar,
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env_vars=("STANFORD_POSTAGGER",),
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searchpath=(),
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url=_stanford_url,
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verbose=verbose,
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)
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self._encoding = encoding
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self.java_options = java_options
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options = {} if options is None else options
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self._options_cmd = ",".join(f"{key}={val}" for key, val in options.items())
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@staticmethod
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def _parse_tokenized_output(s):
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return s.splitlines()
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def tokenize(self, s):
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"""
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Use stanford tokenizer's PTBTokenizer to tokenize multiple sentences.
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"""
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cmd = ["edu.stanford.nlp.process.PTBTokenizer"]
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return self._parse_tokenized_output(self._execute(cmd, s))
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def _execute(self, cmd, input_, verbose=False):
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encoding = self._encoding
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cmd.extend(["-charset", encoding])
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_options_cmd = self._options_cmd
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if _options_cmd:
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cmd.extend(["-options", self._options_cmd])
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default_options = " ".join(_java_options)
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# Configure java.
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config_java(options=self.java_options, verbose=verbose)
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# Windows is incompatible with NamedTemporaryFile() without passing in delete=False.
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with tempfile.NamedTemporaryFile(mode="wb", delete=False) as input_file:
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# Write the actual sentences to the temporary input file
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if isinstance(input_, str) and encoding:
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input_ = input_.encode(encoding)
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input_file.write(input_)
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input_file.flush()
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cmd.append(input_file.name)
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# Run the tagger and get the output.
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stdout, stderr = java(
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cmd, classpath=self._stanford_jar, stdout=PIPE, stderr=PIPE
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)
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stdout = stdout.decode(encoding)
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os.unlink(input_file.name)
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# Return java configurations to their default values.
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config_java(options=default_options, verbose=False)
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return stdout
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