# --*-- coding:utf-8 --*---
_author_ = "ShiXiuquan"

Product_list = [
    ("Iphone X", 8000),
    ("Mi 2", 1200),
    ("HuaWei Pro", 5600),
    ("Oppon Y5", 3000),
    ("Haier X5", 4900),
    ("Hisense H4", 3600),
]
shoppingCart_list = [] # 声明一个空列表
user_salary = input("please salary：")
if user_salary.isdigit(): #判断输入的类型。进行转换为INT，不能直接强转，如果输入Str类型，会报错！
    user_salary = int(user_salary)
    while True:
        print("温馨提示：y查看购物商品清单，q退出程序！")
        for index,item in enumerate(Product_list):
            print(index,item)
        user_chioce = input(">>>>请选择要加入购物车的商品<<<<---：")
        if user_chioce.isdigit():
            user_chioce=int(user_chioce)
            if user_chioce < len(Product_list) and user_chioce >=0: # 判断下标的长度
                P_item = Product_list[user_chioce] # 获取定义下标
                if P_item [1] < user_salary:  
                   shoppingCart_list.append(P_item)
                   user_salary -= P_item[1]
                   print("购买商品\033[31;1m",P_item,"成功！目前余额为",user_salary,"\033[0m""元！")
                else:
                   print("\033[41;1m目前余额为", user_salary, "\033[0m余额不足以购买此商品，购买失败！")
            else:
               print("此商品ID不存在，请重新输入！！！")


        elif user_chioce == "q":
            print("已退出程序！")
        elif user_chioce == "y":
            print(shoppingCart_list)
        else:
            print("输入错误请重新输入！")


以下截图是运行结果输入输出；请参照！！！