Python小程序之购物车

需求：

　　用户入口：

　　1、商品信息放在文件中，从文件中读取

　　2、已购商品，余额记录，第一要输入起始金额，以后不需要二次输入

　　商家入口：

　　2、可以添加商品，修改商品价格

 # Author:Lee Sirimport sys

 def goods_info():
     goods_info = 'goods_info.txt'
     fd = open(goods_info)
     return fd

 def goods_list(fd):
     print('商品列表'.center(30,'-'))
     for items in fd.readlines():
         index,goods_name,goods_price = items.split()
         print(index,goods_name,goods_price)

 def check_cart(buylist):
     print('您的购物车如下：')
     for name,price in buylist:
         print('名称：',name,'价格：',price)
     check_choice = input('是否结账？：[Y/N]')
     if check_choice == 'y' or check_choice == 'Y':
         return True
     else:
         return False

 def check_money(money,buylist):
     money = int(money)
     chech_result = 0
     for name,price in buylist:
         chech_result += int(price)
     if chech_result <= money:
         return True,money - chech_result
     else:
         return False,money

 def buyer():
     buylist = []
     while True:
         money = input("请输入的金钱：")
         if money.isdigit():
             while True:
                 money = int(money)
                 fd = goods_info()
                 goods_list(fd)
                 choice = input('请输出你要购买的商品序号：')
                 if choice.isdigit():
                     choice = int(choice)
                     # print(type(choice))
                     fd.seek(0)
                     if choice > 0  and choice <= len(fd.readlines()):
                         fd.seek(0)
                         #print('1')
                         for items in fd.readlines():
                             index, goods_name, goods_price = items.split()
                             if int(index) == choice:
                                 buylist.append((goods_name,goods_price))
                                 print('添加 %s 至购物车。' % (goods_name))
                                 buy_choice = input('是否继续购买? [Y/N]')
                                 if buy_choice == 'y' or buy_choice == 'Y':
                                     continue
                                 else:
                                     if len(buylist) > 0:
                                         if check_cart(buylist):
                                             check_result, balance = check_money(money,buylist)
                                             if check_result:
                                                 exit('结算成功，您的余额还有 %s' % balance )
                                             else:
                                                 continue_buy = input('您的余额不足，是否修改购物车？: [Y/N]')
                                                 if continue_buy == 'Y' or continue_buy == 'y':
                                                     print('您的购物车如下：')
                                                     for index,buy_name in enumerate(buylist):
                                                         name,price = buy_name
                                                         print('序号：',index,'名称：', name, '价格：', price)
                                                     else:
                                                         while True:
                                                             dele_cart = input('请输入你要删除的产品序号：')
                                                             if dele_cart.isdigit():
                                                                 dele_cart = int(dele_cart)
                                                                 if dele_cart >= 0 and dele_cart <= len(buylist):
                                                                     buylist.remove(dele_cart)
                                                                     break
                                                                 else:
                                                                     print('输入错误请重新输入')
                                                             else:
                                                                 print('输入错误，请重新输入')

                                     else:
                                         continue_check = input('您的购物车为空，是否继续购买? [Y/N]')
                                         if continue_check == 'Y' or continue_check == 'y':
                                             continue
                                         else:
                                             exit('See you tomorrow!')
                     else:
                         print('输入有误，请重新输入：')

                 else:
                     exit('您没有购买任何产品，再见！')
         else:
             print('输入有误，请重新输入')

 buyer()