mirror of https://github.com/explosion/spaCy.git
128 lines
4.4 KiB
Python
128 lines
4.4 KiB
Python
# coding: utf8
|
|
from __future__ import unicode_literals
|
|
|
|
from .symbols import POS, NOUN, VERB, ADJ, PUNCT, PROPN
|
|
from .symbols import VerbForm_inf, VerbForm_none, Number_sing, Degree_pos
|
|
|
|
|
|
class Lemmatizer(object):
|
|
@classmethod
|
|
def load(cls, path, index=None, exc=None, rules=None, lookup=None):
|
|
return cls(index, exc, rules, lookup)
|
|
|
|
def __init__(self, index=None, exceptions=None, rules=None, lookup=None):
|
|
self.index = index
|
|
self.exc = exceptions
|
|
self.rules = rules
|
|
self.lookup_table = lookup if lookup is not None else {}
|
|
|
|
def __call__(self, string, univ_pos, morphology=None):
|
|
if not self.rules:
|
|
return [self.lookup_table.get(string, string)]
|
|
if univ_pos in (NOUN, "NOUN", "noun"):
|
|
univ_pos = "noun"
|
|
elif univ_pos in (VERB, "VERB", "verb"):
|
|
univ_pos = "verb"
|
|
elif univ_pos in (ADJ, "ADJ", "adj"):
|
|
univ_pos = "adj"
|
|
elif univ_pos in (PUNCT, "PUNCT", "punct"):
|
|
univ_pos = "punct"
|
|
elif univ_pos in (PROPN, "PROPN"):
|
|
return [string]
|
|
else:
|
|
return [string.lower()]
|
|
# See Issue #435 for example of where this logic is requied.
|
|
if self.is_base_form(univ_pos, morphology):
|
|
return [string.lower()]
|
|
lemmas = lemmatize(
|
|
string,
|
|
self.index.get(univ_pos, {}),
|
|
self.exc.get(univ_pos, {}),
|
|
self.rules.get(univ_pos, []),
|
|
)
|
|
return lemmas
|
|
|
|
def is_base_form(self, univ_pos, morphology=None):
|
|
"""
|
|
Check whether we're dealing with an uninflected paradigm, so we can
|
|
avoid lemmatization entirely.
|
|
"""
|
|
morphology = {} if morphology is None else morphology
|
|
others = [
|
|
key
|
|
for key in morphology
|
|
if key not in (POS, "Number", "POS", "VerbForm", "Tense")
|
|
]
|
|
if univ_pos == "noun" and morphology.get("Number") == "sing":
|
|
return True
|
|
elif univ_pos == "verb" and morphology.get("VerbForm") == "inf":
|
|
return True
|
|
# This maps 'VBP' to base form -- probably just need 'IS_BASE'
|
|
# morphology
|
|
elif univ_pos == "verb" and (
|
|
morphology.get("VerbForm") == "fin"
|
|
and morphology.get("Tense") == "pres"
|
|
and morphology.get("Number") is None
|
|
and not others
|
|
):
|
|
return True
|
|
elif univ_pos == "adj" and morphology.get("Degree") == "pos":
|
|
return True
|
|
elif VerbForm_inf in morphology or 'VerbForm_inf' in morphology:
|
|
return True
|
|
elif VerbForm_none in morphology or 'VerbForm_none' in morphology:
|
|
return True
|
|
elif Number_sing in morphology or 'Number_sing' in morphology:
|
|
return True
|
|
elif Degree_pos in morphology or 'Degree_pos' in morphology:
|
|
return True
|
|
else:
|
|
return False
|
|
|
|
def noun(self, string, morphology=None):
|
|
return self(string, "noun", morphology)
|
|
|
|
def verb(self, string, morphology=None):
|
|
return self(string, "verb", morphology)
|
|
|
|
def adj(self, string, morphology=None):
|
|
return self(string, "adj", morphology)
|
|
|
|
def punct(self, string, morphology=None):
|
|
return self(string, "punct", morphology)
|
|
|
|
def lookup(self, string):
|
|
if string in self.lookup_table:
|
|
return self.lookup_table[string]
|
|
return string
|
|
|
|
|
|
def lemmatize(string, index, exceptions, rules):
|
|
orig = string
|
|
string = string.lower()
|
|
forms = []
|
|
oov_forms = []
|
|
for old, new in rules:
|
|
if string.endswith(old):
|
|
form = string[: len(string) - len(old)] + new
|
|
if not form:
|
|
pass
|
|
elif form in index or not form.isalpha():
|
|
forms.append(form)
|
|
else:
|
|
oov_forms.append(form)
|
|
# Remove duplicates, and sort forms generated by rules alphabetically.
|
|
forms = list(set(forms))
|
|
# Put exceptions at the front of the list, so they get priority.
|
|
# This is a dodgy heuristic -- but it's the best we can do until we get
|
|
# frequencies on this. We can at least prune out problematic exceptions,
|
|
# if they shadow more frequent analyses.
|
|
for form in exceptions.get(string, []):
|
|
if form not in forms:
|
|
forms.insert(0, form)
|
|
if not forms:
|
|
forms.extend(oov_forms)
|
|
if not forms:
|
|
forms.append(orig)
|
|
return forms
|