购物车

a_list = [
    ('mac',9000),
    ('kindle',8000),
    ('tesla',6000),
    ('python book',105),
]
saving = input('输入你的钱：')
shopping = []
if saving.isdigit():#如果输入的为数字，转换为整型
    saving = int(saving)
    while True:
        for i,v in enumerate(a_list,1):#enumerate在前面加编号，参数1，表示从几开始
            print(i,v)
        choice = input('选择购买商品的编号[退出：q]：')

        if choice.isdigit():
            choice = int(choice)
            if choice>0 and choice<=len(a_list):
                p_item = a_list[choice-1]
                if p_item[1]<saving:
                    saving-=p_item[1]
                    shopping.append(p_item)
                else:
                    print('余额不足，还剩%s块钱'%saving)
                print(p_item)
            else:
                print("商品编号不存在")
        elif choice == 'q':
            print('--------------您已经购买如下商品----------------')
            for i in shopping:
                print(i)
            print("您还剩%s元钱" %saving)
            break
        else:
            print('非法字符')
else:
    print("请正确输入的你钱")