验证英文文本中“a”和“an”的正确使用-Python

Question

我想创建一个程序，从文件中读取文本，并指出“a”和“an”的使用不正确。据我所知，一般规则是，当下一个单词以元音开头时，就用“an”。但它也应该考虑到，也应该从文件中读取异常。在

有人能给我一些建议和窍门，告诉我如何开始这个。可能有帮助的功能。在

我很高兴：-）

我对Python很陌生。在

Answer 1

这里有一个解决方案，其中正确性定义为：an出现在以元音开头的单词之前，否则a可用于：

#!/usr/bin/env python
import itertools
import re
import sys

try:
    from future_builtins import map, zip
except ImportError: # Python 3 (or old Python versions)
    map, zip = map, zip
from operator import methodcaller

import nltk  # $ pip install nltk
from nltk.corpus import cmudict  # >>> nltk.download('cmudict')

def starts_with_vowel_sound(word, pronunciations=cmudict.dict()):
    for syllables in pronunciations.get(word, []):
        return syllables[0][-1].isdigit()  # use only the first one

def check_a_an_usage(words):
    # iterate over words pairwise (recipe from itertools)
    #note: ignore Unicode case-folding (`.casefold()`)
    a, b = itertools.tee(map(methodcaller('lower'), words)) 
    next(b, None)
    for a, w in zip(a, b):
        if (a == 'a' or a == 'an') and re.match('\w+$', w): 
            valid = (a == 'an') if starts_with_vowel_sound(w) else (a == 'a')
            yield valid, a, w

#note: you could use nltk to split text in paragraphs,sentences, words
pairs = ((a, w)
         for sentence in sys.stdin.readlines() if sentence.strip() 
         for valid, a, w in check_a_an_usage(nltk.wordpunct_tokenize(sentence))
         if not valid)

print("Invalid indefinite article usage:")
print('\n'.join(map(" ".join, pairs)))

示例输入（每行一句话）

^{pr2}$

输出

Invalid indefinite article usage:
a acre
an rhythm
an yearly

不清楚为什么最后一对无效，请参见Why is it “an yearly”?