每天一个小程序—0004题（统计单词出现次数）

Posted 2020-10-20 谦谦君子，陌上其华

第 0004 题： 任一个英文的纯文本文件，统计其中的单词出现的个数。

 

先给出我一开始写得，只能说非常不优美，一个一个字符搞得。。。

 1 f = open(\'num.txt\')
 2 word = []
 3 word_num = {}
 4 char = f.read(1)
 5 while char:
 6     if char == \' \' or char == \'\\n\':
 7         if word:
 8             word = \'\'.join(word).lower()  #转成小写
 9             if word in word_num:
10                 word_num[word] += 1
11             else:
12                 word_num[word] = 1
13             word = []
14     else:
15         word.append(char)
16     char = f.read(1)
17 if word:
18     word = \'\'.join(word).lower()
19     if word in word_num:
20         word_num[word] += 1
21     else:
22         word_num[word] = 1
23     word = []
24 for i,j in word_num.items():
25     print(i,j)

 

第二次看了网上的，开始尝试用正则表达式来搞：

 1 import re
 2 
 3 f = open(\'num.txt\')
 4 word_list = []
 5 reg = \'\\w+\'   #/w是匹配字母、数字、下划线
 6 
 7 for line in f:
 8     word = re.findall(reg, line)    #也可以是word = line.split() 
 9     word_list.extend(word)
10 
11 word_set = set(word_list)
12 word_dict = {word: word_list.count(word) for word in word_set}
13 for i, j in word_dict.items():
14     print(i, j)

 

最后就是python自带的collections模块，里面有Counter计数器函数，可以自动统计单词出现次数。

可以先用个例子来了解一下Counter：

1 from collections import Counter
2 
3 word_list = [\'I\', \'am\', \'zyb\', \'zyb\']
4 ans = Counter(word_list)
5 print(ans)

结果为：

 

代码很简洁，如下：

 1 import re
 2 from collections import Counter
 3 
 4 f = open(\'num.txt\')
 5 word_list = []
 6 
 7 for line in f:
 8     word = line.split()
 9     word_list.extend(word)
10 
11 word_dict = dict(Counter(word_list))
12 for i, j in word_dict.items():
13     print(i, j)