是否存在列表中 用for...in..-------------python基础学习

available_toppings = [‘mushrooms’, ‘olives’, ‘green peppers’,
‘pepperoni’, ‘pineapple’, ‘extra cheese’]
❷ requested_toppings = [‘mushrooms’, ‘french fries’, ‘extra cheese’]
❸ for requested_topping in requested_toppings:
❹ if requested_topping in available_toppings:
print(“Adding " + requested_topping + “.”)
❺ else:
print(“Sorry, we don’t have " + requested_topping + “.”)
print(”\nFinished making your pizza!”)