[nltk] Relations Extractor

[constantin01]

Hello

I use nltk.sem.relextract to extract relations in text. I have a problem.

What I do:

1. Tools:

import nltk
import re 
from nltk.chunk import ne_chunk_sents
from nltk.sem import relextract

2. Take simple sentence and prepare it

sent = "China is in Asia"
sent = chunker(nltk.pos_tag(sent.split())) // tokenizing, tagging, chunking in NEs
sent
Tree('S', [Tree('GPE', [('China', 'NNP')]), ('in', 'IN'), Tree('GPE', [('Asia', 'NNP')])])

3. Pattern:

IN = re.compile (r'.*\bin\b(?!\b.+ing)')

4. Processing:

for rel in  nltk.sem.extract_rels('GPE','GPE',sent,corpus='ace',pattern=IN):
   print(nltk.sem.relextract.rtuple(rel))
[]

Fail! What is wrong?