python去除文件中重复的行实例

# -*- coding: UTF-8 -*-
#程序功能是为了完成判断文件中是否有重复句子
#并将重复句子打印出来
 
res_list = []
#f = open('F:/master/master-work/code_of_graduate/LTP_data/raw_plain.txt','r')
f = open('F:/master/master-work/code_of_graduate/chu_li_shuju/ldc-weibo-train-res.txt','r')
res_dup = []
index = 0
file_dul = open('F:/master/master-work/code_of_graduate/chu_li_shuju/ldc-weibo-train-dul.txt', 'w')
for line in f.readlines():
 index = index + 1
 if line in res_list:
  temp_str = ""
  temp_str = temp_str + str(index)     #要变为str才行
  temp_line = ''.join(line)
  temp_str = temp_str+temp_line
  #最终要变为str类型
  file_dul.write(temp_str);       #将重复的存入到文件中
 else:
  res_list.append(line)