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 string("(S(NP I) (VP (V gave) (NP her)))")
>>> sent==t1
True
>>> t1[1][1].set_label('X')
>>> t1[1][1].label()
'X'
>>> print...