為nltk解析樹生成語法規則

Question

如果我有句子"Mary saw a dog"和以下內容：

pos_tags = ['NNP', 'VBD', 'DT', 'NN']

是否可以為該語句生成語法規則，以便可以生成解析樹（以下語法為使用nltk.parse_cfg的語法規則）

sent = "Mary saw a dog".split()
rd_parser = nltk.RecursiveDescentParser(grammar)

for tree in rd_parser.nbest_parse(sent):
    print tree

Answer 1

你可以試試：

import nltk
# Define the cfg grammar.
grammar = nltk.parse_cfg("""
S -> NP VP
NP -> 'DT' 'NN'
VP -> 'VB'
VP -> 'VB' 'NN'
""")


# Make your POS sentence into a list of tokens.
sentence = "DT NN VB NN".split(" ")

# Load the grammar into the ChartParser.
cp = nltk.ChartParser(grammar)

# Generate and print the nbest_parse from the grammar given the sentence tokens.
for tree in cp.nbest_parse(sentence):
    print tree

但是正如@alexis強調的那樣，您要的是幾乎不可能的=）