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I'm trying to identify the subject in a sentence. I tried to use some of the code here:

import spacy
nlp = nlp = spacy.load("en_core_web_sm")
sent = "the python can be used to find objects."
#sent = "The bears in the forest, which has tall trees, are very scary"
doc=nlp(sent)

sentence = next(doc.sents) 

for word in sentence:
    print(word,word.dep_)

This returns the results:

  • the det
  • python nsubjpass
  • can aux
  • be auxpass
  • used ROOT
  • to aux
  • find xcomp
  • objects dobj

I would think in this case the python would be the subject, in most cases that would be the _dep would be nsubj, but its nsubjpass. So if nsubj is not present I can check for nsubjpass but are there any other _dep it could be?

Is there a more robust way to determine subject?

johnny 5
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1 Answers1

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Your sentence is a passive voice example. nsubjpass is the subject when using passive voice

You can find the list of dep_ by calling

for label in nlp.get_pipe("parser").labels:
    print(label, " -- ", spacy.explain(label))

I can see there are 2 more subject types:

csubj  --  clausal subject
csubjpass  --  clausal subject (passive)

One possible way to determine the subject:

if "subj" in word.dep_:
    # continue
krisograbek
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  • Could you give a small explanation of what it means to use a passive voice, and are those the only 2 types of nsubj there are? – johnny 5 Feb 15 '21 at 14:53
  • I edited my answer to provide some more details. The question about passive voice is purely grammatical. I recommend to google about active and passive voice – krisograbek Feb 15 '21 at 16:15
  • Thanks for the help, I accepted the answer I'll do a bit of independent research – johnny 5 Feb 15 '21 at 16:34