文件操作总结(2)

 1 #!/usr/bin/env python
 2 # -*- coding:utf-8 -*-
 3 # Author:James Tao
 4 
 5 #文件修改
 6 #将文件更改之后写到新文件
 7 
 8 find_str='我有太多歌曲永远不会被唱起'
 9 replace_str='YOUTAIDUODEGEQUYONGYUANBUHUIBEICHANGQI'
10 
11 f=open('yesterday','r',encoding='utf-8')#原文件
12 f_new=open('yesterday.bak','w',encoding='utf-8')#新文件
13 for line in f:#f为一个迭代器，按行迭代
14     if find_str in line:
15         line=line.replace(find_str,replace_str)#字符串替换replace函数
16     f_new.write(line)
17 f.close()
18 f_new.close()
19 
20 
21 #用with打开文件,省去close步骤
22 with open('yesterday','r',encoding='utf-8') as f:
23     for line in f:
24         print(line)
25 
26 
27 #用with可以打开多个文件
28 find_str='我有太多歌曲永远不会被唱起'
29 replace_str='YOUTAIDUODEGEQUYONGYUANBUHUIBEICHANGQI'
30 
31 with open('yesterday','r',encoding='utf-8') as f1, \
32         open('yesterday.bak', 'w', encoding='utf-8') as f2:
33     for line in f1:
34         if find_str in line:
35             line=line.replace(find_str,replace_str)
36         f2.write(line)