python文件实现增删改查操作

 # coding = utf-8

 import os
 import json
 import re
 '''
 本程序旨在将练习基础知识部分，包括：
 列表，元组，字典，文件，函数，字符串等知识
 实现的功能：
 1.查询
 2.删除
 3.更改
 4.增加
 '''

 #定义的文档存储格式
 mes_style = '''bankend    www.baidu.org
            server 192.168.50.21   wight 100   maxconn 300
 bankend    www.oldboy.org
            server 192.168.99.31   wight 50   maxconn 100\n
 '''

 #用户只能修改这些字段的值
 updateable ={
     1:"server",
     2:"wight",
     3:"maxconn"
 }

 #菜单
 menu_info = '''
 1.查询
 2.删除
 3.修改
 4.添加
 5.退出
 '''

 #展示菜单
 def show_menu():
     '''
     to display the menu ,I chosed the str to show it

     '''
     print(menu_info)

 #初始化操作，往文件里边添加格式文件
 def before_start():
     '''
     before start,you can call this func to create a file
     and then you should explanatory(注释) this method before calling
     the main method
     '''
     f = open("web.property","a+",encoding="utf-8")
     for i in mes_style:
         f.writelines(i)
     f.close()
 #before_start()
 #查询记录
 def search(user_enter):
     '''
     this function can be used when search function needed
    user can select the listed item and then,the corresponding
    entry will be display
     '''
     #查询并打印出用户查询关键字所在的行和下一行
     f = open("web.property","r",encoding="utf-8")
     list = f.readlines()
     for i,line in enumerate(list):
         if user_enter in line:
             print(line)
             print(list[i+1])
         elif i == len(list)-1:
             print("查无结果")
     f.close()

 #查出所有的文件内容，并包装成字典返回
 def searchall():
     '''
     this function is a common function ,it can used in delete and update,so add
     '''
     f = open("web.property", "r", encoding="utf-8")
     list = f.readlines()
     #用来存储找到value为空所对应的key
     list1 =[]
     mapc = {}
     for i,line in enumerate(list):
         if line == "\n" or line == "":
             list.pop(i)
     for i in range(0,len(list),2):
         mapc[int(i/2)+1] =list[i:i+2]
     f.close()
     return mapc
 #删除
 def delete():
     '''
     this function is used to delete the record user selected
     '''
     flag = True
     while flag:
         maps = searchall()
         for i in maps.items():
             print(i)
         user_selected = input("请选择要删除的对象(输入b返回)：")
         if user_selected.isdigit():
             user_selected = int(user_selected)
             #print(list)
             for j in maps.keys():
                 if user_selected == j:
                     temp = j
             for m in maps.items():
                 if user_selected == m:
                     temp = m
                     #删除文件中对应的该条记录
                     for line in list(maps.keys()):
                         if temp== line:
                             maps.pop(temp)
                             file_path = "C:/Users/Administrator/PycharmProjects/pythondemo/web.propertybak"
                             if os.path.exists(file_path):
                                 os.remove(file_path)
                             os.renames("web.property", "web.propertybak")
                             f6 = open("web.property", "w")
                             for line in maps.values():
                                 f6.write(line[0])
                                 f6.write(line[1])
                             f6.close()
                             break
                         else:
                             break
                     print(maps)
                     #询问是否继续
                     conti = input("是否继续删除？（y/n）:")
                     if conti == "y":
                         continue
                     else:
                         flag = False
                         break
         elif user_selected == "b":
             break
         else:
             print("输入有错误，请重新选择")

 #添加
 def add():
     '''
     you can execute add funciton to add a node to file
     but you should according to those forms
     1:"server",
     2:"wight",
     3:"maxconn"
     '''
     #regs ={"bankend":"www.\w.com","server":"\d.\d.\d.\d"}

     while True:
         print("请依次填入下列选项中的值")
         bankend = input("bankend:")
         server = input("server:")
         wight = input("wight:")
         maxconn = input("maxconn:")
         # 正则表达式检查输入是否符合格式要求
         if re.compile(r"www\.(\w+)(\.com|\.cn|\.org|\.net)").match(bankend):
             print("bankend ok")
             if re.compile(r"\d+\.\d+\.\d+\.\d").match(server):
                 print("server ok")
                 if re.compile(r"\d").match(wight):
                     print("wight ok")
                     if re.compile(r"\d").match(maxconn):
                         print("maxconn ok")
                         #条件都符合
                         write_date =["bankend    %s\n"%bankend,"           server %s   wigth %d   maxconn %d"%(server,int(wight),int(maxconn))]
                         f = open("web.property", "a", encoding="utf-8")
                         for line in write_date:
                             f.writelines(line)
                         f.close()
                         break
                     else:
                         print("maxconn invalid")
                         continue
                 else:
                     print("wight invalid")
                     continue
             else:
                 print("server invalid")
                 continue
         else:
             print("bankend invalid")
             continue

 #更新
 def update():
     '''
     this function is designed for update the file message,content
     '''
     state = 0
     while True:
         mapa = searchall()
         for i,m in enumerate(mapa):
             print(str(i+1)+"."+str(mapa[m]))
         it = input("请选择要更改的条目:(b 返回)")
         if it.isdigit():
             it = int(it)
             for i in mapa.keys():
                 if it == i:
                     print("check pass")
                     while True:
                         for member in updateable:
                             print(str(member)+":"+updateable[member])
                         user_se = input("请选择要修改的字段(按b返回)：")
                         if user_se.isdigit():
                             user_se =int(user_se)
                             for j in updateable.keys():
                                 if user_se == j:
                                     print("check pass2")
                                     while True:
                                         update_to = input("请输入值：")
                                         if update_to==None or update_to=="":
                                             pass
                                         else:
                                             break
                                     print(user_se)
                                     #获得选择的字段
                                     map_attr = updateable[user_se]
                                     li =[]
                                     for  l in mapa[it]:
                                         if map_attr in l:
                                             li.append(l.split("   "))
                                         print(l)
                                     #print(li)
                                     for i,ind in enumerate(li[0]):
                                         if(map_attr in ind and map_attr == "server"):
                                             ind = "           "+map_attr+" "+(str(update_to) if update_to.isdigit() else update_to)
                                         elif (map_attr in ind ):
                                             ind = "  " + map_attr + " " + (str(update_to) if update_to.isdigit()  else update_to)
                                             li[0][i]=ind
                                             break
                                     #同步到mapa
                                     final_str =""
                                     for i in li[0]:
                                         if "server" in i:
                                             final_str += "          "+i+"   "
                                         elif "wight" in i:
                                             final_str +=i+"   "
                                         else:
                                             final_str += i
                                     #print(final_str)
                                     for i,n in enumerate(mapa[it]):
                                         if "server" in n:
                                             mapa[it][i] =final_str+"\n"
                                     print(mapa)
                                     with open("web.property","w") as f:
                                         for line in mapa.values():
                                             f.writelines(line)
                                     f.close()
                                     print(mapa)
                                     print(li)
                                     print("修改成功")
                                     break
                                 elif j == len(updateable):
                                     print("不在选项内，请重新选择")
                         elif user_se == "b":
                             break
                 elif i ==len(mapa):
                     print("输入选项不在列表中，请重新选择")
         elif it == "b":
             state = 1
             break
         else:
             print("输入有误")
     if state == 1:
         return

 #主程序
 while True:
     show_menu()
     selected = input("请选择:(1,2，3，4，5):")
     if selected.isdigit():
         selected = int(selected)
         if selected == 1:
             search(input("请输入要查询的网址："))
         if selected == 2:
             delete()
         if selected == 3:
             update()
         if selected == 4:
             add()
         if selected == 5:
             break
     else:
         print("你输入了其他字符，请输入数字")
         continue