Description¶
Implement the generate() method for NLTK’s probabilistic context-free grammar to probabilistically generate valid sentences. (NLTK stands for Natural Language Toolkit.)
Example usage¶
A PCFG can be initialized in the same way that an NLTK probabilistic context-free grammar is initialized:
>>> from pcfg import PCFG
>>> grammar = PCFG.fromstring("""
... S -> Subject Action [1.0]
... Subject -> "a cow" [0.7] | "some guy" [0.1] | "the woman" [0.2]
... Action -> "eats lunch" [0.5] | "was here" [0.5]
... """)
To generate sentences, simply use the generate() method:
>>> for sentence in grammar.generate(3):
... print(sentence)
The output could be the following:
>>> for sentence in grammar.generate(3):
... print(sentence)
The output could be the following:
>>> for sentence in grammar.generate_sentences(3):
... print(sentence)
The output could be the following:
the woman eats lunch
the woman was here
a cow was here
Of course, your output may be different because the sentences are generated probabilistically.