Metrics based on syntactic matching
Syntactic matching can be done by performing the task of chunking. In NLTK, a module called nltk.chunk.api is provided that helps to identify chunks and returns a parse tree for a given chunk sequence.
The module called nltk.chunk.named_entity is used to identify a list of named entities and also to generate a parse structure. Consider the following code in NLTK based on syntactic matching:
>>> import nltk >>> from nltk.tree import Tree >>> print(Tree(1,[2,Tree(3,[4]),5])) (1 2 (3 4) 5) >>> ct=Tree('VP',[Tree('V',['gave']),Tree('NP',['her'])]) >>> sent=Tree('S',[Tree('NP',['I']),ct]) >>> print(sent) (S (NP I) (VP (V gave) (NP her))) >>> print(sent[1]) (VP (V gave) (NP her)) >>> print(sent[1,1]) (NP her) >>> t1=Tree.from ...Get Natural Language Processing: Python and NLTK now with the O’Reilly learning platform.
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