python学习日记day3

#----------------------购物车程序---------------------------

stopping_list=[
    ("Iphone4",1400),
    ("Iphone5",2500),
    ("Iphone6",3000),
    ("Iphone7",3500),
    ("Iphone8",4500),
    ("Iphonex",6500),
]
stopping_cart=[]
salary=input("Please enter your salary:")
if salary.isdigit():
    salary=int(salary)
    while True:
        for index,item in enumerate(stopping_list):
            print(index,item)
        user_choice=input("Please enter the serial number of the goods you want to purchase:")
        if user_choice.isdigit():
            user_choice=int(user_choice)
            if user_choice<len(stopping_list) and user_choice>=0:
                if stopping_list[user_choice][1]<=salary:
                    salary-=stopping_list[user_choice][1];
                    stopping_cart.append(stopping_list[user_choice])
                    print("The goods you bought have been added to the shopping cart.")
                    print("Your balance is:", salary)
                    print()
                else:
                    print("Your balance is not enough!")
                    print("Goods failed to join a shopping cart!")
                    print()
            else:
                print("The goods were not found")

        elif user_choice=='q':
            print("-------stopping_cart-------")
            for index, item in enumerate(stopping_cart):
                print(index, item)
            print("Your balance is:", salary)
            exit()
        else:
            print("Invalid command!")



　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　2018-04-22  23:59:08