python - 从文件中的 n 行 block 中提取项目，计算每个 block 的项目频率，Python

Question

我有一个文本文件，其中包含 5 行制表符分隔行 block :

 1 \t DESCRIPTION \t SENTENCE \t ITEMS

 1 \t DESCRIPTION \t SENTENCE \t ITEMS

 1 \t DESCRIPTION \t SENTENCE \t ITEMS

 1 \t DESCRIPTION \t SENTENCE \t ITEMS

 1 \t DESCRIPTION \t SENTENCE \t ITEMS

 2 \t DESCRIPTION \t SENTENCE \t ITEMS

 2 \t DESCRIPTION \t SENTENCE \t ITEMS

 2 \t DESCRIPTION \t SENTENCE \t ITEMS

 2 \t DESCRIPTION \t SENTENCE \t ITEMS

 2 \t DESCRIPTION \t SENTENCE \t ITEMS

等等

在每个 block 中，DESCRIPTION 和 SENTENCE 列是相同的。感兴趣的数据位于 ITEMS 列中，该列对于 block 中的每一行都不同，并且采用以下格式:

word1, word2, word3

...等等

对于每个5行 block ，我需要统计word1、word2等在ITEMS中的频率。例如，如果第一个 5 行 block 如下

 1 \t DESCRIPTION \t SENTENCE \t word1, word2, word3

 1 \t DESCRIPTION \t SENTENCE \t word1, word2

 1 \t DESCRIPTION \t SENTENCE \t word4

 1 \t DESCRIPTION \t SENTENCE \t word1, word2, word3

 1 \t DESCRIPTION \t SENTENCE \t word1, word2

那么这个 5 行 block 的正确输出将是

1, SENTENCE, (word1: 4, word2: 4, word3: 2, word4: 1)

即， block 编号，后面跟着句子，后面跟着单词的频率计数。

我有一些代码来提取五行 block ，并在提取后计算 block 中单词的频率，但我坚持隔离每个 block 、获取单词频率、继续下一个 block 的任务，等等

from itertools import groupby 

def GetFrequencies(file):
    file_contents = open(file).readlines()  #file as list
    """use zip to get the entire file as list of 5-line chunk tuples""" 
    five_line_increments = zip(*[iter(file_contents)]*5) 
    for chunk in five_line_increments:  #for each 5-line chunk... 
        for sentence in chunk:          #...and for each sentence in that chunk
            words = sentence.split('\t')[3].split() #get the ITEMS column at index 3
            words_no_comma = [x.strip(',') for x in words]  #get rid of the commas
            words_no_ws = [x.strip(' ')for x in words_no_comma] #get rid of the whitespace resulting from the removed commas


       """STUCK HERE   The idea originally was to take the words lists for 
       each chunk and combine them to create a big list, 'collection,' and
       feed this into the for-loop below."""





    for key, group in groupby(collection): #collection is a big list containing all of the words in the ITEMS section of the chunk, e.g, ['word1', 'word2', word3', 'word1', 'word1', 'word2', etc.]
        print key,len(list(group)),    

Answer 1

使用Python 2.7

#!/usr/bin/env python

import collections

chunks={}

with open('input') as fd:
    for line in fd:
        line=line.split()
        if not line:
            continue
        if chunks.has_key(line[0]):
            for i in line[3:]:
                chunks[line[0]].append(i.replace(',',''))
        else:
            chunks[line[0]]=[line[2]]

for k,v in chunks.iteritems():
    counter=collections.Counter(v[1:])
    print k, v[0], counter

输出:

1 SENTENCE Counter({'word1': 3, 'word2': 3, 'word4': 1, 'word3': 1})