python - 一种类轮语法python

Question

我想计算一个文件中每个单词的数量，然后尝试编写它
作为一行代码，但是我收到无效的语法错误，而且我不明白为什么，
或如何更改它。

我的代码:

def print_words(filename):
  my_file = open(filename, 'r')
  word_dict = {}
  for line in my_file:
    line.lower()
    words_in_line = line.split(" ")
    word_dict[word] += 1 if word_dict.get(word) else word_dict[word] = 0 
      for word in words_in_line

错误信息:

word_dict[word] += 1 if word_dict.get(word) else word_dict[word] = 0 for word in words_in_line
                                                                 ^
SyntaxError: invalid syntax

我也尝试写一些不同的东西(代码将跟随)，但仍然出现相同的错误。但是当我删除“= 0”时，语法就可以了(当我从原始的一个衬里删除它时，语法仍然是无效的)。

my_file = open(filename, 'r')
word_dict = {}
for line in my_file:
  line.lower()
  words_in_line = line.split(" ")
  for word in words_in_line:
    word_dict[word] += 1 if word_dict.get(word) else word_dict[word] = 0

Answer 1

您可以使用正则表达式来获取单词，并使用Counter类(来自集合)对单词进行计数:

from collections import Counter
import re
with open("testfile.txt") as file: words = Counter(re.findall("\w+",file.read()))

如果文件很大，则可能需要逐行处理:

with open("testfile.txt") as file: words = Counter( w for line in file for w in re.findall("\w+",line.upper()))