从文件中获取字数，忽略python中的注释行

Question

I am trying to count number of occurrences of a word from a file, using Python. But I have to ignore comments in the file.

I have a function like this:

def getWordCount(file_name, word):
  count = file_name.read().count(word)
  file_name.seek(0)
  return count

How to ignore where the line begins with a # ?

I know this can be done by reading the file line by line like stated in this question . Are there any faster, more Pythonian way to do so ?

Answer 1

You can do one thing just create a file that is not having the commented line then run your code Ex.

infile = file('./file_with_comment.txt')

newopen = open('./newfile.txt', 'w')
for line in infile :
    li=line.strip()
    if not li.startswith("#"):
        newopen.write(line)

newopen.close()

This will remove every line startswith # then run your function on newfile.txt

def getWordCount(file_name, word):
  count = file_name.read().count(word)
  file_name.seek(0)
  return count

Answer 2

More Pythonian would be this:

def getWordCount(file_name, word):
  with open(file_name) as wordFile:
    return sum(line.count(word)
      for line in wordFile
      if not line.startswith('#'))

Faster (which is independent from being Pythonian) could be to read the whole file into one string, then use regexps to find the words not in a line starting with a hash.

Answer 3

You can use a regular expression to filter out comments:

import re

text = """ This line contains a word. # empty
This line contains two: word word  # word
newline
# another word
"""

filtered = ''.join(re.split('#.*', text))
print(filtered)
#  This line contains a word. 
# This line contains two: word word  
# newline

print(text.count('word'))  # 5
print(filtered.count('word'))  # 3

Just replace text with your file_name.read() .