如何从文本中查找肯定和否定单词的总数？

Question

我想查找给定文本中匹配的肯定和否定单词的总数。我在positive.txt文件中有肯定词列表，在文件中有否定词列表negative.txt。如果一个单词与肯定单词列表中的单词匹配，那么我想要一个简单的整数变量，该变量的值增加1，与否定匹配单词相同。从我给定的代码中，我得到了下面的一段@class=[story-hed]。这是我要与肯定和否定单词列表以及单词总数进行比较的文本。我的代码是

from scrapy.spider import BaseSpider
from scrapy.selector import HtmlXPathSelector
from dawn.items import DawnItem

class dawnSpider(BaseSpider):
   name = "dawn"
   allowed_domains = ["dawn.com"]
   start_urls = [
       "http://dawn.com/"
   ]

   def parse(self, response):

      hxs = HtmlXPathSelector(response)      
      sites = hxs.select('//h3[@class="story-hed"]//a/text()').extract()
      items=[]

      for site in sites:
         item=DawnItem()
         item['title']=site
         items.append(item)
      return items

Answer 1

下面的独立代码可以达到目的：

from collections import Counter

def readwords( filename ):
    f = open(filename)
    words = [ line.rstrip() for line in f.readlines()]
    return words

positive = readwords('positive.txt')
negative = readwords('negative.txt')

paragraph = 'this is really bad and in fact awesome. really awesome.'

count = Counter(paragraph.split())

pos = 0
neg = 0
for key, val in count.iteritems():
    key = key.rstrip('.,?!\n') # removing possible punctuation signs
    if key in positive:
        pos += val
    if key in negative:
        neg += val

print pos, neg

这是两个输入文件中的内容：

positive.txt：

good 
awesome

negative.txt：

bad
ugly

输出为：2 1

要抓紧实施，您可能需要使用项目管道http://doc.scrapy.org/en/latest/topics/item-pipeline.html