product_list = [
('Mac', 9000),
('kindle', 800),
('tesla', 900000),
('python book', 105),
('bike', 2000)
]
saving = input('please input your saving:')
shopping_car = []
if saving.isdigit():
saving = int(saving)
while True:
for i,v in enumerate(product_list,1):
print(i,v)
choice = input('选择购买商品编号[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)
else:
print('余额不足， 还剩%s'%saving)
print(p_item)
else:
print('编码不存在')
elif choice == 'q':
print('------您已经购买如下商品------')
for i in shopping_car:
print(i)
print('您还剩%s元钱'%saving)
break
else:
print("invalid input")
