购物系统编写

购物系统编写

项目结构

bin目录

1. start.py(启动文件，串联所有功能)

   import sys,os
   my_path = os.getcwd()
   sys.path.append(os.path.join(my_path,'..','core'))
   import login,register,add_shop_car,settlement
   
   dict1 = {
       '1':'\t登录',
       '2':'\t注册',
       'q':'\t退出'
   }
   dict2 = {
       '1':'\t购物',
       '2':'\t结算',
       'q':'\t退出'
   }
   
   while True:
       # 输出指令字典
       for i in dict1:
           print(i, dict1[i])
       choise = input('请输入指令>>>').strip()
       if choise == 'q':
           break
       elif choise == '1':
           username = login.login()
           if len(username) == 0:
               continue
           else:
               while True:
                   # 输出指令字典
                   for i in dict2:
                       print(i, dict2[i])
                   choise = input('请输入指令>>>').strip()
                   if choise == 'q':
                       break
                   elif choise == '1':
                       add_shop_car.addShopCar(username)
                   elif choise == '2':
                       settlement.settlement(username)
                   else:
                       print('命令有误，请重试')
       elif choise == '2':
           register.register()
       else:
           print('命令有误，请重试')
   

core目录

1. login.py(登录功能)

   # 登录功能
   import os,sys
   my_path = os.getcwd()
   sys.path.append(os.path.join(my_path,"..",'lib'))
   import user_data
   def login():
       username = input('请输入用户名>>>').strip()
       password = input('请输入密码>>>').strip()
       user_info = user_data.getUser(username)
       if user_info == 0:
           print('用户名不存在')
           return False
       elif user_info['password'] == password:
           print(f'{username},登陆成功')
           return username
       else:
           print('密码错误')
           return False
   
   

2. register.py(注册功能)

   # 注册功能
   import user_data
   def register():
       username = input('请输入一个用户名>>>').strip()
       # 查重
       if len(user_data.getUser(username)) == 0:
           password = input('请输入密码>>>').strip()
           dict_user = {"username":username,"password":password,"balance":15000,"shop_car":{}}
           user_data.create(dict_user)
           print(f'{username},注册成功')
           return True
       else:
           print(f'{username}已存在')
           return False
   

3. add_shop_car.py(选购功能，商品添加到购物车)

   # 添加商品到购物车
   import user_data
   def addShopCar(username):
       shop_list = [
           ['挂壁面', 3],
           ['印度飞饼', 22],
           ['极品木瓜', 666],
           ['土耳其土豆', 999],
           ['伊拉克拌面', 1000],
           ['董卓戏张飞公仔', 2000],
           ['仿真玩偶', 10000]
       ]
       # 创建购物车容器{'商品':['单价'，数量]}
       shop_car = {}
       num = 0
       tag_list = {'tag1': True, 'tag2': True,'tag3':True}
       while tag_list['tag1']:
           for i in shop_list:
               print(f'商品编号:{num}\t商品名称:{i[0]}\t商品单价:{i[1]}元')
               num += 1
           choise = input('请输入想要购买的商品序号,输入q退出>>>').strip()
           if choise == 'q':
               tag_list['tag1'] = False
           elif not choise.isdigit():
               print('请输入正确的商品编号')
           elif int(choise) < 0 and int(choise) > len(shop_list):
               print('商品不存在')
           else:
               while tag_list['tag2']:
                   shop_number = input('请输入想要购买的数量,输入q退出>>>').strip()
                   if shop_number == 'q':
                       tag_list['tag2'] = False
                   elif not shop_number.isdigit():
                       print('请输入正确的数量')
                   elif int(shop_number) < 0:
                       print('请输入正确的数量')
                   else:
                       shop_item = {shop_list[int(choise)][0]:[shop_list[int(choise)][1],int(shop_number)]}
                       while tag_list['tag3']:
                           chiose_sure = input(f'确认添加购物车{shop_list[int(choise)][0]},单价{shop_list[int(choise)][1]}元,数量{shop_number}个,y/n?')
                           if chiose_sure == 'y':
                               shop_car.update(shop_item)
                               user_info = user_data.getUser(username)  # 取出用户信息
                               shop_car_dict = user_info['shop_car']  # 取出原有购物车数据
                               shop_car_dict.update(shop_car)  # 合并购物车数据
                               user_info['shop_car'] = shop_car_dict  # 新的购物车数据替换老的
                               user_data.createUser(user_info)  # 重新写入用户信息
                               tag_list['tag2'] = False
                               tag_list['tag3'] = False
                           elif chiose_sure == 'n':
                               tag_list['tag3'] = False
                           else:
                               print('命令错误')
   

4. settlement.py(结算功能)

   # 结算功能
   import user_data
   def settlement(username):
       # 算出总金额
       acount = 0
       user_info = user_data.getUser(username)  # 用户信息
       shop_car = user_info['shop_car']
       while True:
           for i in shop_car.values():
               acount += int(i[0])*int(i[1])  # 获取待支付金额
           choise = input(f'当前账户余额{user_info["balance"]},待支付{acount},是否支付y/n?')
           if choise == 'y':
               balance = int(user_info["balance"]) - int(acount)
               if balance >= 0:
                   user_info['balance'] = balance
                   user_info['shop_car'] = {}
                   user_data.createUser(user_info)
                   print(f'支付成功，当前余额{balance}元')
                   return
               else:
                   print('余额不足，请充值')
                   return
           elif choise =='n':
               return
           else:
               print('命令错误')
   

lib目录

1. user_data.py(公共功能，读写文件操作)

   import json,os
   
   my_path = os.path.dirname(__file__)
   # 取用户信息，反序列化后输出
   def getUser(username):
       try:
           with open(fr'{my_path}\..\db\{username}.txt', 'r', encoding='utf8') as f:
               res = f.read()
               user_info = json.loads(res)
           return user_info
       except FileNotFoundError:
           return 0
   
   
   # 注册，修改用户
   def createUser(user_dict):
       username = user_dict['username']
       with open(fr'{my_path}\..\db\{username}.txt', 'w', encoding='utf8') as f1:
           res = json.dump(user_dict,f1)
   

编写思路

1. 分析数据存储模式
   1. 数据以文件形式存储，所以创建db文件，内部存放txt类型数据文件
   2. 数据格式和需要的内容，需要以json格式存储，例：{"username": "oscar", "password": "oscar123", "balance": 14934, "shop_car":
2. 分析需求
   1. 需要用到大量的读写操作，可以定义成公共功能模块供调用
   2. 需要登录，注册，选购，结算四个主要功能