spaCy/spacy/lang/pl/lemmatizer.py
2020-05-21 20:52:48 +02:00

107 lines
3.6 KiB
Python

# coding: utf-8
from __future__ import unicode_literals
from ...lemmatizer import Lemmatizer
from ...parts_of_speech import NAMES
class PolishLemmatizer(Lemmatizer):
# This lemmatizer implements lookup lemmatization based on
# the Morfeusz dictionary (morfeusz.sgjp.pl/en) by Institute of Computer Science PAS
# It utilizes some prefix based improvements for
# verb and adjectives lemmatization, as well as case-sensitive
# lemmatization for nouns
def __init__(self, lookups, *args, **kwargs):
# this lemmatizer is lookup based, so it does not require an index, exceptionlist, or rules
super(PolishLemmatizer, self).__init__(lookups)
self.lemma_lookups = {}
for tag in [
"ADJ",
"ADP",
"ADV",
"AUX",
"NOUN",
"NUM",
"PART",
"PRON",
"VERB",
"X",
]:
self.lemma_lookups[tag] = self.lookups.get_table(
"lemma_lookup_" + tag.lower(), {}
)
self.lemma_lookups["DET"] = self.lemma_lookups["X"]
self.lemma_lookups["PROPN"] = self.lemma_lookups["NOUN"]
def __call__(self, string, univ_pos, morphology=None):
if isinstance(univ_pos, int):
univ_pos = NAMES.get(univ_pos, "X")
univ_pos = univ_pos.upper()
if univ_pos == "NOUN":
return self.lemmatize_noun(string, morphology)
if univ_pos != "PROPN":
string = string.lower()
if univ_pos == "ADJ":
return self.lemmatize_adj(string, morphology)
elif univ_pos == "VERB":
return self.lemmatize_verb(string, morphology)
lemma_dict = self.lemma_lookups.get(univ_pos, {})
return [lemma_dict.get(string, string.lower())]
def lemmatize_adj(self, string, morphology):
# this method utilizes different procedures for adjectives
# with 'nie' and 'naj' prefixes
lemma_dict = self.lemma_lookups["ADJ"]
if string[:3] == "nie":
search_string = string[3:]
if search_string[:3] == "naj":
naj_search_string = search_string[3:]
if naj_search_string in lemma_dict:
return [lemma_dict[naj_search_string]]
if search_string in lemma_dict:
return [lemma_dict[search_string]]
if string[:3] == "naj":
naj_search_string = string[3:]
if naj_search_string in lemma_dict:
return [lemma_dict[naj_search_string]]
return [lemma_dict.get(string, string)]
def lemmatize_verb(self, string, morphology):
# this method utilizes a different procedure for verbs
# with 'nie' prefix
lemma_dict = self.lemma_lookups["VERB"]
if string[:3] == "nie":
search_string = string[3:]
if search_string in lemma_dict:
return [lemma_dict[search_string]]
return [lemma_dict.get(string, string)]
def lemmatize_noun(self, string, morphology):
# this method is case-sensitive, in order to work
# for incorrectly tagged proper names
lemma_dict = self.lemma_lookups["NOUN"]
if string != string.lower():
if string.lower() in lemma_dict:
return [lemma_dict[string.lower()]]
elif string in lemma_dict:
return [lemma_dict[string]]
return [string.lower()]
return [lemma_dict.get(string, string)]
def lookup(self, string, orth=None):
return string.lower()
def lemmatize(self, string, index, exceptions, rules):
raise NotImplementedError