python - 查找句子字符串中单词的不同实现 - Python

Question

(这个问题与一般的字符串检查有关，而不是自然语言处理本身，但如果您将其视为 NLP 问题，请想象它不是当前分析器可以分析的语言，为了简单起见，我将使用英文字符串作为示例)

假设一个单词只有 6 种可能的形式

1. 首字母大写
2. 其复数形式带有“s”
3. 其复数形式带有“es”
4. 大写+“es”
5. 大写+“s”
6. 不带复数或大写的基本形式

假设我想找到句子中出现的任何形式的单词coach的第一个实例的索引，是否有更简单的方法来执行这两种方法:

长 if 条件

sentence = "this is a sentence with the Coaches"
target = "coach"

print target.capitalize()

for j, i in enumerate(sentence.split(" ")):
  if i == target.capitalize() or i == target.capitalize()+"es" or \
     i == target.capitalize()+"s" or i == target+"es" or i==target+"s" or \
     i == target:
    print j

迭代 try- except

variations = [target, target+"es", target+"s", target.capitalize()+"es",
target.capitalize()+"s", target.capitalize()]

ind = 0
for i in variations:
  try:
    j == sentence.split(" ").index(i)
    print j
  except ValueError:
    continue

Answer 1

我建议看看NLTK的stem包:http://nltk.org/api/nltk.stem.html

使用它，您可以“从单词中删除形态词缀，只留下词干。词干算法旨在删除语法角色、时态、派生形态等所需的词缀，只留下词干。”

如果当前 NLTK 未涵盖您的语言，您应该考虑扩展 NLTK。如果您确实需要一些简单的东西并且不关心 NLTK，那么您仍然应该将代码编写为小型的、易于组合的实用函数的集合，例如:

import string 

def variation(stem, word):
    return word.lower() in [stem, stem + 'es', stem + 's']

def variations(sentence, stem):
    sentence = cleanPunctuation(sentence).split()
    return ( (i, w) for i, w in enumerate(sentence) if variation(stem, w) )

def cleanPunctuation(sentence):
    exclude = set(string.punctuation)
    return ''.join(ch for ch in sentence if ch not in exclude)

def firstVariation(sentence, stem):
    for i, w  in variations(sentence, stem):
        return i, w

sentence = "First coach, here another two coaches. Coaches are nice."

print firstVariation(sentence, 'coach')

# print all variations/forms of 'coach' found in the sentence:
print "\n".join([str(i) + ' ' + w for i,w in variations(sentence, 'coach')])