文件修改、文件操作、自动关闭文件 

 1 文件修改
 2 # f = open("user.txt",encoding="utf-8")
 3 # a = f.read()
 4 # b = a.replace("nihaosadf","你好")
 5 # # print(b)
 6 # f.close()
 7 #
 8 # f = open("user.txt",'w',encoding="utf-8")
 9 # f.write(b)
10 # f.close()
11 # print(b)
12 
13 # f = open("user.txt",'a+',encoding="utf-8")
14 # f.seek(0)
15 # result = f.read()
16 # result_new = result.replace("nihaosadf","你好")
17 # f.seek(0)
18 # f.truncate() #清空文件
19 # f.write(result_new)
20 # f.close()
21 import os
22 f1 = open("user.txt",encoding="utf-8")
23 f2 = open("user.txt.bat","w",encoding="utf-8")  #w可以创建文件并可以写入
24 for i in f1:
25     result=i.replace("周","周杰伦")
26     f2.write(result)
27 f1.close()
28 f2.close()
29 
30 os.remove("user.txt")
31 os.rename("user.txt.bat","user.txt")
32 
33 
34 
35 文件操作
36 # r+    w+     a+
37 # 读写 写读 追加读模式
38 # r相关，文件不存在都会报错，他的文件指针在最前面
39 # w相关，都会创建文件，都会清空文件内容
40 # a相关，如果要读，那么就移动文件指针，不管你怎么移动文件指针，写的时候都是追加在后面
41 
42 # f = open("user.txt","r+",encoding="utf-8")
43 # f.read()
44 # f.write("是的是")
45 # f.close()
46 
47 # f = open("user.txt","w+",encoding="utf-8")
48 # f.write("nihaosadfas")
49 # f.seek(0)
50 # print(f.read())
51 # f.close()
52 
53 # f = open("user.txt","a+",encoding="utf-8")
54 # f.seek(0)
55 # print(f.read())
56 # f.write("ni")
57 # f.close()
58 f = open("access.log",encoding="utf-8")
59 # a = f.tell()  #告诉你指针的位置
60 # print(f,a)
61 for line in f:
62     print(line)
63 f.close()
64 
65 
66 
67 自动关闭文件
68 with open("user.txt",encoding="utf-8") as f,open("user.txt2",'w') as f2:
69     for line in f:
70         new_file = line.replace("周杰伦","周")
71         f2.write(new_file)
72

 

posted @ 2021-05-13 17:53  等待iing  阅读(91)  评论(0)    收藏  举报