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Official python interface for Stanford CoreNLP

Project description

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This package contains a python interface for Stanford CoreNLP that contains a reference implementation to interface with the Stanford CoreNLP server. The package also contains a base class to expose a python-based annotation provider (e.g. your favorite neural NER system) to the CoreNLP pipeline via a lightweight service.

To use the package, first download the official java CoreNLP release, unzip it, and define an environment variable $CORENLP_HOME that points to the unzipped directory.


Annotation Server Usage

import corenlp

text = "Chris wrote a simple sentence that he parsed with Stanford CoreNLP."

# We assume that you've downloaded Stanford CoreNLP and defined an environment
# variable $CORENLP_HOME that points to the unzipped directory.
# The code below will launch StanfordCoreNLPServer in the background
# and communicate with the server to annotate the sentence.
with corenlp.CoreNLPClient(annotators="tokenize ssplit".split()) as client:
  ann = client.annotate(text)

# You can access annotations using ann.
sentence = ann.sentence[0]

# The corenlp.to_text function is a helper function that
# reconstructs a sentence from tokens.
assert corenlp.to_text(sentence) == text

# You can access any property within a sentence.
print(sentence.text)

# Likewise for tokens
token = sentence.token[0]
print(token.lemma)

# Use tokensregex patterns to find who wrote a sentence.
pattern = '([ner: PERSON]+) /wrote/ /an?/ []{0,3} /sentence|article/'
matches = client.tokensregex(text, pattern)
# sentences contains a list with matches for each sentence.
assert len(matches["sentences"]) == 1
# length tells you whether or not there are any matches in this
assert matches["sentences"][0]["length"] == 1
# You can access matches like most regex groups.
matches["sentences"][1]["0"]["text"] == "Chris wrote a simple sentence"
matches["sentences"][1]["0"]["1"]["text"] == "Chris"

# Use semgrex patterns to directly find who wrote what.
pattern = '{word:wrote} >nsubj {}=subject >dobj {}=object'
matches = client.semgrex(text, pattern)
# sentences contains a list with matches for each sentence.
assert len(matches["sentences"]) == 1
# length tells you whether or not there are any matches in this
assert matches["sentences"][0]["length"] == 1
# You can access matches like most regex groups.
matches["sentences"][1]["0"]["text"] == "wrote"
matches["sentences"][1]["0"]["$subject"]["text"] == "Chris"
matches["sentences"][1]["0"]["$object"]["text"] == "sentence"

See test_client.py and test_protobuf.py for more examples. Props to @dan-zheng for tokensregex/semgrex support.

Annotation Service Usage

NOTE: The annotation service allows users to provide a custom annotator to be used by the CoreNLP pipeline. Unfortunately, it relies on experimental code internal to the Stanford CoreNLP project is not yet available for public use.

import corenlp
from .happyfuntokenizer import Tokenizer

class HappyFunTokenizer(Tokenizer, corenlp.Annotator):
    def __init__(self, preserve_case=False):
        Tokenizer.__init__(self, preserve_case)
        corenlp.Annotator.__init__(self)

    @property
    def name(self):
        """
        Name of the annotator (used by CoreNLP)
        """
        return "happyfun"

    @property
    def requires(self):
        """
        Requires has to specify all the annotations required before we
        are called.
        """
        return []

    @property
    def provides(self):
        """
        The set of annotations guaranteed to be provided when we are done.
        NOTE: that these annotations are either fully qualified Java
        class names or refer to nested classes of
        edu.stanford.nlp.ling.CoreAnnotations (as is the case below).
        """
        return ["TextAnnotation",
                "TokensAnnotation",
                "TokenBeginAnnotation",
                "TokenEndAnnotation",
                "CharacterOffsetBeginAnnotation",
                "CharacterOffsetEndAnnotation",
               ]

    def annotate(self, ann):
        """
        @ann: is a protobuf annotation object.
        Actually populate @ann with tokens.
        """
        buf, beg_idx, end_idx = ann.text.lower(), 0, 0
        for i, word in enumerate(self.tokenize(ann.text)):
            token = ann.sentencelessToken.add()
            # These are the bare minimum required for the TokenAnnotation
            token.word = word
            token.tokenBeginIndex = i
            token.tokenEndIndex = i+1

            # Seek into the txt until you can find this word.
            try:
                # Try to update beginning index
                beg_idx = buf.index(word, beg_idx)
            except ValueError:
                # Give up -- this will be something random
                end_idx = beg_idx + len(word)

            token.beginChar = beg_idx
            token.endChar = end_idx

            beg_idx, end_idx = end_idx, end_idx

annotator = HappyFunTokenizer()
# Calling .start() will launch the annotator as a service running on
# port 8432 by default.
annotator.start()

# annotator.properties contains all the right properties for
# Stanford CoreNLP to use this annotator.
with corenlp.CoreNLPClient(properties=annotator.properties, annotators="happyfun ssplit pos".split()) as client:
    ann = client.annotate("RT @ #happyfuncoding: this is a typical Twitter tweet :-)")

    tokens = [t.word for t in ann.sentence[0].token]
    print(tokens)

See test_annotator.py for more examples.

Project details


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