spaCy/spacy/lang/de/syntax_iterators.py
2017-06-04 15:51:50 -05:00

39 lines
1.4 KiB
Python

# coding: utf8
from __future__ import unicode_literals
from ...symbols import NOUN, PROPN, PRON
def noun_chunks(obj):
"""
Detect base noun phrases from a dependency parse. Works on both Doc and Span.
"""
# this iterator extracts spans headed by NOUNs starting from the left-most
# syntactic dependent until the NOUN itself for close apposition and
# measurement construction, the span is sometimes extended to the right of
# the NOUN. Example: "eine Tasse Tee" (a cup (of) tea) returns "eine Tasse Tee"
# and not just "eine Tasse", same for "das Thema Familie".
labels = ['sb', 'oa', 'da', 'nk', 'mo', 'ag', 'ROOT', 'root', 'cj', 'pd', 'og', 'app']
doc = obj.doc # Ensure works on both Doc and Span.
np_label = doc.vocab.strings.add('NP')
np_deps = set(doc.vocab.strings.add(label) for label in labels)
close_app = doc.vocab.strings.add('nk')
rbracket = 0
for i, word in enumerate(obj):
if i < rbracket:
continue
if word.pos in (NOUN, PROPN, PRON) and word.dep in np_deps:
rbracket = word.i+1
# try to extend the span to the right
# to capture close apposition/measurement constructions
for rdep in doc[word.i].rights:
if rdep.pos in (NOUN, PROPN) and rdep.dep == close_app:
rbracket = rdep.i+1
yield word.left_edge.i, rbracket, np_label
SYNTAX_ITERATORS = {
'noun_chunks': noun_chunks
}