写了一个简单的购物车

# 商品列表
shopping_list = [("apple",15),("iphone",8000),("water",30),("vivo",3000)]
saving = input("请输入整数金额：")  # 引导用户输入金额
setting = False  # 判断用户输入的金额是否有误
if saving.isdigit():
    saving = int(saving)
    setting = True
else:
    print("请输入正确的金额")
shopping_car = []  # 创建购物车
while setting:
    # 打印所有商品
    for i in range(0, len(shopping_list)):
        print(i, ":", shopping_list[i])
    # 开始选择商品
    choice = input("请选择你要购买的商品序号[q退出]：")
    if choice.isdigit():
        if int(choice) not in range(0,len(shopping_list)):
            print("还没有此类商品！")
        else:
            shopping = shopping_list[int(choice)]  # 顾客所选商品及价格
            price = shopping[1]  # 顾客所选商品价格
            if saving >= price:
                shopping_car.append(shopping)
                saving -= price
                print(shopping_car, "\n", "您还剩余%d钱" % saving)
            elif saving < price:
                print(shopping, saving, "哎呀！钱好像不够。")
    elif choice == "q":
        print(shopping_car, saving)
        break
    else:
        print("""请输入商品前的序号""")