更改文件，某一行

 1 def fetch(data):
 2     print('这是查询功能')
 3     tag = False
 4     data = 'aaaa %s\n'%data
 5     res_data = []
 6     with open('bbb','r',encoding='gbk') as file:
 7         for i in file:
 8             if i == data:
 9                 tag = True
10                 continue
11             if tag == True and i.startswith('aaa'):
12                 break
13             if tag == True:
14                 res_data.append(i)
15                 print(i)
16     return res_data
17 def add():
18     pass
19 def delete():
20     pass
21 def change(data):
22     print('你要更改的数据是%s'%data)
23     old_addr =data[0]['backend']
24     old_to = "        server  %s  98798  %s\n"%(data[0]['record']['server'],data[0]['record']['98798'])
25     need_to = "        server  %s  98798  %s\n"%(data[1]['record']['server'],data[1]['record']['98798'])
26     res = fetch(old_addr)
27     print(res)
28     if old_to in res:
29         a = res.index(old_to)
30         res[a] = need_to
31         res.insert(0,'aaaa %s\n'%old_addr)
32         tag = False
33         write_or = True
34         old_addr2 = 'aaaa %s'%old_addr
35         with open('bbb','r') as old_file,\
36                 open('bbb_new','w') as new_file:
37             for backend in old_file:
38                 if backend.strip() == old_addr2:
39                     tag = True
40                     continue
41                 elif backend.startswith('aaaa'):
42                     tag = False
43                 if not tag:
44                     new_file.write(backend)
45                 if tag and write_or:
46                     for i in res:
47                         new_file.write(i)
48                     write_or = False
49 
50     else:
51         print('没有要修改的数据')
52     return '更改成功'
53 
54 if __name__ =="__main__":
55     msg = '''
56     1：查询
57     2；增加
58     3：删除
59     4：更改
60     5：退出'''
61     func_list = {
62         '1':fetch,
63         '2':add,
64         '3':delete,
65         '4':change
66     }
67     while True:
68         print(msg)
69         choice = input("请输入需要选择的功能：")
70         if not choice: continue
71         if choice =='5':break
72         data = input('请输入数据：')
73         if choice != '1':
74             data = eval(data)
75         ress = func_list[choice](data)
76         print(ress)
77 输出：
78     1：查询
79     2；增加
80     3：删除
81     4：更改
82     5：退出
83 请输入需要选择的功能：4
84 请输入数据：[{'backend':'www.asia.com','record':{'server':'jdfjsk','98798':'sajdfkjahskjf'}},{'backend':'www.asia.com','record':{'server':'aaaaa','98798':'bbbbbb'}}]
85 你要更改的数据是[{'backend': 'www.asia.com', 'record': {'server': 'jdfjsk', '98798': 'sajdfkjahskjf'}}, {'backend': 'www.asia.com', 'record': {'server': 'aaaaa', '98798': 'bbbbbb'}}]
86 这是查询功能
87         server  jdfjsk  98798  sajdfkjahskjf
88 
89         server  jdfjsdsk  98798  sajdfksasjahskjf
90 
91         server  jdfsdjsk  98798  sajdfksdjahskjf
92 
93         server  jdfxcjsk  98798  sajdfkjsaahskjf
94 
95         server  jdfjsxck  98798  sajdfkxxzjahskjf
96 
97 ['        server  jdfjsk  98798  sajdfkjahskjf\n', '        server  jdfjsdsk  98798  sajdfksasjahskjf\n', '        server  jdfsdjsk  98798  sajdfksdjahskjf\n', '        server  jdfxcjsk  98798  sajdfkjsaahskjf\n', '        server  jdfjsxck  98798  sajdfkxxzjahskjf\n']
98 None