spaCy/spacy/lemmatizer.py
2016-01-16 10:00:57 +01:00

97 lines
2.6 KiB
Python

from __future__ import unicode_literals, print_function
from os import path
import codecs
try:
import ujson as json
except ImportError:
import json
from .parts_of_speech import NOUN, VERB, ADJ, PUNCT
from .util import get_package
class Lemmatizer(object):
@classmethod
def load(cls, via):
return cls.from_package(get_package(via))
@classmethod
def from_package(cls, pkg):
index = {}
exc = {}
for pos in ['adj', 'noun', 'verb']:
with pkg.open(('wordnet', 'index.%s' % pos), default=None) as file_:
index[pos] = read_index(file_) if file_ is not None else set()
with pkg.open(('wordnet', '%s.exc' % pos), default=None) as file_:
exc[pos] = read_exc(file_) if file_ is not None else {}
rules = pkg.load_json(('vocab', 'lemma_rules.json'), default={})
return cls(index, exc, rules)
def __init__(self, index, exceptions, rules):
self.index = index
self.exc = exceptions
self.rules = rules
def __call__(self, string, pos):
if pos == NOUN:
pos = 'noun'
elif pos == VERB:
pos = 'verb'
elif pos == ADJ:
pos = 'adj'
elif pos == PUNCT:
pos = 'punct'
lemmas = lemmatize(string, self.index.get(pos, {}), self.exc.get(pos, {}), self.rules.get(pos, []))
return lemmas
def noun(self, string):
return self(string, 'noun')
def verb(self, string):
return self(string, 'verb')
def adj(self, string):
return self(string, 'adj')
def punct(self, string):
return self(string, 'punct')
def lemmatize(string, index, exceptions, rules):
string = string.lower()
forms = []
if string in index:
forms.append(string)
forms.extend(exceptions.get(string, []))
for old, new in rules:
if string.endswith(old):
form = string[:len(string) - len(old)] + new
if form in index or not form.isalpha():
forms.append(form)
if not forms:
forms.append(string)
return set(forms)
def read_index(fileobj):
index = set()
for line in fileobj:
if line.startswith(' '):
continue
pieces = line.split()
word = pieces[0]
if word.count('_') == 0:
index.add(word)
return index
def read_exc(fileobj):
exceptions = {}
for line in fileobj:
if line.startswith(' '):
continue
pieces = line.split()
exceptions[pieces[0]] = tuple(pieces[1:])
return exceptions