#Author:ersa

 '''

 程序：购物车程序

 需求:

 启动程序后，让用户输入工资，然后打印商品列表

 允许用户根据商品编号购买商品

 用户选择商品后，检测余额是否够，够就直接扣款，不够就提醒

 可随时退出，退出时，打印已购买商品和余额

 #知识点：len(market):列表长度（列表中的条目个数）

        isdigit() 判断输入的内容是否是数字，TRUE 是数字

        取列表数据 enumerate

        for index,item in enumerate(market)

             print(index, item)

     输出内容高亮显示 "\033[31;1m%s\033[0m"%(balance)

     退出程序使用exit()方法

 '''

 market = [[1,"iphone",5800],

           [2,"Mac Pro", 12000],

           [3,"Starbuck Latte",31],

           [4,"Alex Python",88],

           [5,"bike",1800]]

 balance = input("please input salary: ")

 if balance.isdigit():

     balance = int(balance)

 else:

     exit("Illegal value, please re-enter")

 amount = 0

 print("Tip: type q to exit.\n\n")

 shopping_cart = []

 while True:

     for commodity in market:

         print(commodity)

     user_choice = input("Please enter a product number or q：\n")

     if user_choice == "q":

         break

     if user_choice.isdigit():

         user_choice = int(user_choice)

         if 0 < user_choice and user_choice <= (len(market)+1):

             amount += market[user_choice - 1][2];

             if balance < amount:

                 print("Reminder: the balance is insufficient, please re-purchase.\n")

                 continue

             shopping_cart.append(market[user_choice - 1])

         else:

             print("If you do not have this item, please reselect it !\n")

             continue

 print("List of purchased items:\n")

 for commodity in shopping_cart:

     print(commodity)

 print("Payment amount: \033[41;1m%s\033[0m"%(amount))

 balance -= amount

 print("your balance: \033[31;1m%s\033[0m \n"%balance)