nltk.grammar.induce_pcfg

nltk.grammar.induce_pcfg(start, productions)[source]

Induce a PCFG grammar from a list of productions.

The probability of a production A -> B C in a PCFG is:

count(A -> B C)
P(B, C | A) = ————— where * is any right hand side
count(A -> *)
Parameters

  • start (Nonterminal) – The start symbol

  • productions (list(Production)) – The list of productions that defines the grammar