python ------- 文件处理之增删改查-------作业

注：这里的文件都是.txt格式的

1，查询：

只需一个文件，源文件是：“haporxy.conf”

2，删除：

因为文件是不能删除，这里使用写入的方式，需要建两个文件，

源文件：“haporxy.conf”

写入文件： “test5”

3，增加：

在文件末尾增加一个语句，需要两个文件。

源文件：“haproxy.conf”

写入文件：“test3”

4，修改：

需要两个文件。

源文件：：“haproxy.conf”

写入文件：“test6”

5，有点小bug，还待改进，

6，代码如下:

1.查询：

输入：www.ordboy1.org

 1 list = []  #创建一个空列表
 2 flag = False #设置一个开关
 3 input1 = input("plesae your input "www.oldboy1.org" :")
 4 with open("haproxy.conf",encoding="utf-8") as f_read:  #把源文件以utf-8格式打开到f_read
 5     for line in f_read:  #遍历文件到line这个变量中
 6         if line.startswith("backend") and input1 in line: 
 7             flag = True
 8             continue  #跳出本层循环
 9 
10         if line.startswith("backend"): #判断字符串是否以backend开头
11             break
12         if flag:
13             list.append(line.strip()) #追加到空列表
14 print("hello".center(50,"-"))
15 
16 for i in list:  #遍历列表
17     print(i)

2.删除：

输入：{"backend":"www.oldboy20.org","record":{"server":1111,"weight":2222,"maxconn":3333}}

 1 choice = input("please your input  is {} :")
 2     # {"backend":"www.oldboy20.org","record":{"server":1111,"weight":2222,maxconn:3333}}
 3     dic = eval(choice)  # 把输入的字符串转成字典
 4     tltle = dic["backend"]
 5     tetle1 = dic["record"]  #这个没有用
 6     with open("haproxy.conf", encoding="utf-8") as f_read, open("test5", "w", encoding="utf-8") as w_write:
 7 
 8         for line in f_read:
 9             w_write.write(line)
10             if line.startswith("backend") and tltle in line:
11                 # w_write.write(line)
12                 break

3.增加:

输入：{"backend":"www.oldboy20.org","record":{"server":1111,"weight":2222,"maxconn":3333}}

 1 choice = input("please your input is {}  : ")
 2     # {"backend":"www.oldboy20.org","record":{"server":1111,"weight":2222,"maxconn":3333}}
 3     dic = eval(choice)  # 把字符串转成字典
 4     title = dic['backend']  # "www.oldboy20.org"
 5     record = dic['record']
 6     r_s = '        server %s weight %s maxconn %s
' 
 7           % (record['server'], record['weight'], record['maxconn'])
 8 
 9     with open("haproxy.conf", encoding="utf-8") as f_read, open("test3", mode="w", encoding="utf-8") as w_read:
10         for line in f_read:
11             w_read.write(line)
12             if line.startswith('backend') and title in line:
13                 # print('11111>')
14                 w_read.write(r_s)
15                 # w_read.write('=====>')
16         w_read.flush()

4.修改：

输入：{"backend":"www.oldboy20.org","record":{"server":1111,"weight":2222,"maxconn":3333}}

 1 choice = input("please your input is {} :")
 2     # {"backend":"www.oldboy20.org","record":{"server":1111,"weight":2222,"maxconn":3333}}
 3     dic = eval(choice)  #把输入的字符串转成字典
 4     tltel = dic["backend"]
 5     tltel1 = dic["record"]
 6     dic["record"]["server"] = "0000"
 7     dic["record"]["weight"] = "0000"
 8     dic["record"]["maxconn"] = "0000"
 9     # print(dic)
10     #格式化字符串
11     r_s = "        server %s weight %s maxconn %s" % (tltel1["server"], tltel1['weight'], tltel1["maxconn"])
12     with open("haproxy.conf", encoding="utf-8") as f_read, open("test6", mode="w", encoding="utf-8") as w_write:
13         for line in f_read:
14             w_write.write(line) # 把line中的字符串写到w_write中
15             if line.startswith("backend") and tltel in line: #判断 line中字符串否以“backend”开头，并且满不满足tetle在这行
16                 w_write.write(r_s)  #把字符串写入到w_rite中
17                 break   #跳出循环