购物车程序

product_list = [
("Mac",9000),
("kindle",800),
("tesla",900000),
("python book",105),
("bike",2000),
]
saving = input ("plsease input your money:")
shopping_car = []
if saving.isdigit():#验证是否为数字
saving = int(saving)
while True :

for i,v in enumerate(product_list,1):#i为用户自己定义的变量，in后面是一个列表 range(5)相当于一个0到4的列表
#print(product_list.index(i),i) #enumerate 是给列表里每个元组加一个序号的
print(i,".",v)#用两个变量接收列表值
choice = input("请选择购买商品的编号【退出：q】：")
if choice.isdigit():
choice = int(choice)
if choice> 0 and choice<=len(product_list):
p_item = product_list[choice-1]
if p_item[1]< saving:
saving-= p_item[1]
shopping_car.append(p_item)
print("您已把%s放入购物车，还剩%s"%(product_list[choice-1],saving))
else:
print("余额不足，还剩%s"%saving)
print(p_item)
else:
print("编码不存在")
elif choice == "q":
print("-----------您已经购买如下商口--------------")
for i in shopping_car:
print(i)
print("您还剩%s元钱"%saving)
break
else:
print("invalid input")