product_list = [(‘iphone‘,5800),
                (‘max pro‘,9800),
                (‘bike‘,800),
                (‘watch‘,10600),
                (‘coffee‘,31),
                (‘alex python‘,120)]
salary = input("请输入工资：")

shopp_list = []
if salary.isdigit():
    salary = int(salary)
    while True:
        for index,item in  enumerate(product_list):
            print(index,item)
        user_choice = input("请选择商品编号：")
        if user_choice.isdigit():
            user_choice = int(user_choice)
            if user_choice <= len(product_list) and user_choice >=0:
                p_item = product_list[user_choice]
                if p_item[1] <= salary:
                    shopp_list.append(p_item)
                    salary -=p_item[1]
                    print("added %s into shopping cart,your current balan" %shopp_list)
                else:
                    print("您的余额：%s"%user_choice)

            else:
                print("product code [%d] is not exits "%user_choice)

        elif user_choice == "q":
            print("------------------shopping list---------------")
            for p in  shopp_list:
                print(p)
            print("you current balance:%s"%salary)
            exit()
        else:
            print("invalid option")