在Python 3.3.2中计算词组频率 [英] Counting phrase frequency in Python 3.3.2

问题描述

我一直在研究Web上的不同来源，并尝试了各种方法，但只能找到如何计算唯一单词而不是唯一短语的频率.到目前为止，我的代码如下:

I have been examining different sources on the web and have tried various methods but could only find how to count the frequency of unique words but not unique phrases. The code I have so far is as follows:

import collections
import re
wanted = set(['inflation', 'gold', 'bank'])
cnt = collections.Counter()
words = re.findall('\w+', open('02.2003.BenBernanke.txt').read().lower())
for word in words:
    if word in wanted:
        cnt [word] += 1
print (cnt)

如果可能的话，我也想计算一下在本文中使用中央银行"和高通货膨胀"这一短语的次数.感谢您提供的任何建议或指导.

If possible, I would also like to count the number of times the phrases 'central bank' and 'high inflation' is used in this text. I appreciate any suggestion or guidance you can give.

推荐答案

首先，这就是我将生成的cnt生成方式(以减少内存开销)

First of all, this is how I would generate the cnt that you do (to reduce memory overhead)

def findWords(filepath):
  with open(filepath) as infile:
    for line in infile:
      words = re.findall('\w+', line.lower())
      yield from words

cnt = collections.Counter(findWords('02.2003.BenBernanke.txt'))

现在，关于您的词组问题:

Now, on to your question about phrases:

from itertools import tee
phrases = {'central bank', 'high inflation'}
fw1, fw2 = tee(findWords('02.2003.BenBernanke.txt'))   
next(fw2)
for w1,w2 in zip(fw1, fw2)):
  phrase = ' '.join([w1, w2])
  if phrase in phrases:
    cnt[phrase] += 1

希望这会有所帮助

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