小程序-shopping car

product_list = [("mac",9000),
                ("bike",1500),
                ("book",80),
                ("tesla",900000),
                ("kindle",800)] #此处需注意：元组的书写方式，如果写成了"mac,9000"，则9000的格式为string且无法比较
salary = input("please input your salary:")
shopping_car = []
if salary.isdigit():
    salary = int(salary)
    while True:
        for i,v in enumerate(product_list,1):#enumerate每次回返回一个tuple：(index, value)
            print(i, ">>>",v)
        # while True:  # 如果条件判断语句永远为 true，循环将会无限的执行下去,此处表示可以循环选择
        choice =input("please enter your choice[q:quit]:")#如果将choice 缩进了，一次只得到一个输出1 >>> mac,9000
        # 2>>>bike,1500 3>>>book，80，因为 enumerate 函数表示遍历该列表，如果缩进相当于 i=1,选择一次；i=2，选择一次
        #i =3,又选择一次，循环的层次不对
        if choice.isdigit():
            choice = int(choice)
            if choice >0  and  choice<= len(product_list) :#为什么用for choice >0  and  choice<= len(product_list)报错，can't assign to operator
                p_item = product_list[choice-1]
                if p_item[1] < salary:
                    salary -= p_item[1]
                    shopping_car.append(p_item)
                else:
                    print("余额不足")
            else:
                print("选择不在商品列表中")
        elif choice == "q":
            print("退出，您已购买如下商品")
            for a in shopping_car:#遍历
                print(a)

            # print(shopping_car)
            print("余额%s"%salary)
            break
        else:
            print("请输入数字")
else:
    print("please input digits.")

转载于:https://www.cnblogs.com/ljk21313/p/6958953.html