Question

已编辑我需要解析以下句子：“列出飞往丹佛的航班座位”。下面的代码应该工作，但不是。问题在于nltk.CFG.fromstring命令，我相信其他功能都有效。有什么想法如何在这里正确定义语法规则？

import nltk
from nltk.corpus import treebank



# here we define a grammar


import nltk
from nltk.corpus import treebank

grammar = nltk.CFG.fromstring("""

S -> NP VP | VP |IVP

IVP -> IV NP NP PP | IV NP NP

NP -> NNS | Det Nom | 'Denver'

Nom -> Nom N | Nom PP | N

VP -> V NP PP | V PP  | V NP | V | TO VP

PP -> IN NP | PRP NP


Det ->'the'
IN -> 'on'
TO -> 'to'
PRP ->'me'
N ->'flight'
NNS -> 'seats'
V ->  'List'
 """)



# here we let nltk construct a chart parser from our grammar
parser = nltk.ChartParser(grammar)

# input: a list of words
# returns all the parses of a sentence
def allParses(sentenceList):
    return parser.parse(sentenceList)

# input: a list of parse trees
# prints all the parse trees
def printParses(parses):
    for tree in parses:
        print(tree)

# input: a sentence as a string or as a list of words
# prints a sentence, then parses it and prints all the parse trees
def processSentence(sentence):
    sentenceList = sentence
    if isinstance(sentence,str):
        sentenceList = sentence.split(' ')
    print('Original sentence: ' + ' '.join(sentenceList))
    printParses(allParses(sentenceList))

def mainScript():
    processSentence('List me the seats on the flight to Denver')

感谢您的帮助。

Answer 1

＆＃34;列表＆＃34;也可以是名词：N - > ＆＃39;列表＆＃39;
也许还在箭头和单词之间加上空格：
N - ＆gt;＆＃39;航班＆＃39;应该是N - > ＆＃39;飞行＆＃39; | ＆＃39;列表＆＃39;
＆＃34;座位＆＃34;也可以是一个动词。例如：＆＃34;她座位＆＃34;或者＆＃34;他座位＆＃34;
规则也不完整。例如，IV没有规则 - > ??

nltk CFG，定义语法规则

1 个答案: