我今天才知道中文的冒号（：）和英文的冒号（:）不一样，惊了。

代码

product_list=[
    ("ipad",3896),
    ("phone",3299),
    ("headset",2199),
    ("vip",999)
]
shopping_list=[]
salary=input("your salary is:")
if salary.isdigit():
    salary=int(salary)
    while True:
        for index,item in enumerate(product_list):
            print(index,item)
        user_choice=input("please choose which you wanna:")
        if user_choice.isdigit():
            user_choice=int(user_choice)
            if user_choice<len(product_list) and user_choice>=0:
                p_item=product_list[user_choice]
                if p_item[1]<=salary:
                    shopping_list.append(p_item)
                    salary-=p_item[1]
                    print("Added %s into shopping cart,your current balance is %s"%(p_item,salary))
                else:
                    print("your salary is not enough.")
            else:
                print("produt code [%s] is not exist."%user_choice)
        elif user_choice=="q":
            print("-----------shoping list------------")
            for p in shopping_list:
                print(p)
            print("your current balance is:",salary)
            exit()
        else:
            print("invalid optiom")
else:
    print("Do you have money???")