python删除文本中行数标签的方法

# -*- coding:utf-8 -*- 
import re 
import os 
import sys 
reload(sys) 
sys.setdefaultencoding('utf-8') 
 
ls = os.linesep 
label_regex = r'\d+.\t' 
content = [] 
for line in open('source.txt', 'r'): 
  mm = re.search(label_regex, line) 
  if mm: 
    mm = mm.group() 
    content.append(line.replace(mm, '').rstrip()) 
  else: 
    break 
f = open('source.txt', 'w') 
f.writelines(['%s%s' % (x,ls) for x in content])