152 lines
5.2 KiB
Python
152 lines
5.2 KiB
Python
# -*- coding: utf-8 -*-
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# Natural Language Toolkit: Interface to the HunPos POS-tagger
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#
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# Copyright (C) 2001-2019 NLTK Project
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# Author: Peter Ljunglöf <peter.ljunglof@heatherleaf.se>
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# Dávid Márk Nemeskey <nemeskeyd@gmail.com> (modifications)
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# Attila Zséder <zseder@gmail.com> (modifications)
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# URL: <http://nltk.org/>
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# For license information, see LICENSE.TXT
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"""
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A module for interfacing with the HunPos open-source POS-tagger.
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"""
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import os
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from subprocess import Popen, PIPE
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from six import text_type
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from nltk.internals import find_binary, find_file
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from nltk.tag.api import TaggerI
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_hunpos_url = "http://code.google.com/p/hunpos/"
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_hunpos_charset = "ISO-8859-1"
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"""The default encoding used by hunpos: ISO-8859-1."""
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class HunposTagger(TaggerI):
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"""
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A class for pos tagging with HunPos. The input is the paths to:
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- a model trained on training data
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- (optionally) the path to the hunpos-tag binary
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- (optionally) the encoding of the training data (default: ISO-8859-1)
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Example:
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>>> from nltk.tag import HunposTagger
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>>> ht = HunposTagger('en_wsj.model')
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>>> ht.tag('What is the airspeed of an unladen swallow ?'.split())
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[('What', 'WP'), ('is', 'VBZ'), ('the', 'DT'), ('airspeed', 'NN'), ('of', 'IN'), ('an', 'DT'), ('unladen', 'NN'), ('swallow', 'VB'), ('?', '.')]
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>>> ht.close()
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This class communicates with the hunpos-tag binary via pipes. When the
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tagger object is no longer needed, the close() method should be called to
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free system resources. The class supports the context manager interface; if
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used in a with statement, the close() method is invoked automatically:
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>>> with HunposTagger('en_wsj.model') as ht:
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... ht.tag('What is the airspeed of an unladen swallow ?'.split())
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...
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[('What', 'WP'), ('is', 'VBZ'), ('the', 'DT'), ('airspeed', 'NN'), ('of', 'IN'), ('an', 'DT'), ('unladen', 'NN'), ('swallow', 'VB'), ('?', '.')]
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"""
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def __init__(
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self, path_to_model, path_to_bin=None, encoding=_hunpos_charset, verbose=False
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):
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"""
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Starts the hunpos-tag executable and establishes a connection with it.
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:param path_to_model: The model file.
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:param path_to_bin: The hunpos-tag binary.
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:param encoding: The encoding used by the model. Unicode tokens
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passed to the tag() and tag_sents() methods are converted to
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this charset when they are sent to hunpos-tag.
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The default is ISO-8859-1 (Latin-1).
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This parameter is ignored for str tokens, which are sent as-is.
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The caller must ensure that tokens are encoded in the right charset.
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"""
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self._closed = True
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hunpos_paths = [
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".",
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"/usr/bin",
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"/usr/local/bin",
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"/opt/local/bin",
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"/Applications/bin",
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"~/bin",
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"~/Applications/bin",
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]
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hunpos_paths = list(map(os.path.expanduser, hunpos_paths))
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self._hunpos_bin = find_binary(
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"hunpos-tag",
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path_to_bin,
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env_vars=("HUNPOS_TAGGER",),
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searchpath=hunpos_paths,
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url=_hunpos_url,
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verbose=verbose,
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)
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self._hunpos_model = find_file(
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path_to_model, env_vars=("HUNPOS_TAGGER",), verbose=verbose
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)
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self._encoding = encoding
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self._hunpos = Popen(
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[self._hunpos_bin, self._hunpos_model],
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shell=False,
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stdin=PIPE,
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stdout=PIPE,
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stderr=PIPE,
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)
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self._closed = False
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def __del__(self):
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self.close()
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def close(self):
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"""Closes the pipe to the hunpos executable."""
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if not self._closed:
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self._hunpos.communicate()
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self._closed = True
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def __enter__(self):
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return self
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def __exit__(self, exc_type, exc_value, traceback):
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self.close()
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def tag(self, tokens):
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"""Tags a single sentence: a list of words.
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The tokens should not contain any newline characters.
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"""
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for token in tokens:
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assert "\n" not in token, "Tokens should not contain newlines"
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if isinstance(token, text_type):
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token = token.encode(self._encoding)
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self._hunpos.stdin.write(token + b"\n")
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# We write a final empty line to tell hunpos that the sentence is finished:
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self._hunpos.stdin.write(b"\n")
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self._hunpos.stdin.flush()
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tagged_tokens = []
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for token in tokens:
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tagged = self._hunpos.stdout.readline().strip().split(b"\t")
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tag = tagged[1] if len(tagged) > 1 else None
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tagged_tokens.append((token, tag))
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# We have to read (and dismiss) the final empty line:
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self._hunpos.stdout.readline()
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return tagged_tokens
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# skip doctests if Hunpos tagger is not installed
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def setup_module(module):
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from nose import SkipTest
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try:
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HunposTagger("en_wsj.model")
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except LookupError:
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raise SkipTest("HunposTagger is not available")
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