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41 lines
1.4 KiB
Python
41 lines
1.4 KiB
Python
from ...pipeline import Lemmatizer
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from ...tokens import Token
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class EnglishLemmatizer(Lemmatizer):
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"""English lemmatizer. Only overrides is_base_form."""
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def is_base_form(self, token: Token) -> bool:
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"""
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Check whether we're dealing with an uninflected paradigm, so we can
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avoid lemmatization entirely.
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univ_pos (unicode / int): The token's universal part-of-speech tag.
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morphology (dict): The token's morphological features following the
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Universal Dependencies scheme.
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"""
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univ_pos = token.pos_.lower()
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morphology = token.morph.to_dict()
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if univ_pos == "noun" and morphology.get("Number") == "Sing":
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return True
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elif univ_pos == "verb" and morphology.get("VerbForm") == "Inf":
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return True
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# This maps 'VBP' to base form -- probably just need 'IS_BASE'
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# morphology
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elif univ_pos == "verb" and (
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morphology.get("VerbForm") == "Fin"
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and morphology.get("Tense") == "Pres"
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and morphology.get("Number") is None
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):
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return True
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elif univ_pos == "adj" and morphology.get("Degree") == "Pos":
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return True
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elif morphology.get("VerbForm") == "Inf":
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return True
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elif morphology.get("VerbForm") == "None":
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return True
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elif morphology.get("Degree") == "Pos":
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return True
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else:
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return False
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