有关Python继承的面向对象设计

Question

class Player:

    def __init__(self, name=None):
        self.name = name
        self.score = 0

    def add_score(self, score):
        self.score = self.score + score



class HumanPlayer(Player):

    def __init__(self):
        Player.__init__(self, name="Human")


class ComputerPlayer(Player):

    def __init__(self):
        Player.__init__(self, name="Eliza")


class Score:

    def __init__(self, human, computer):
        self.human = human
        self.computer = computer

    def add_score(self, player, score):
        self.player.add_score(score)

My problem is with the add_score method in the Score class.

In Python context:

Since both human and computer are inherited from the Player class (they have their own methods, but omitted in this question), how can I refer either of them in the add_score method? (To be clear: I want to say add_score to any object inherited from the Player class. [Does it matter if meant “ add_score to any object either from the Player class or to any object inherited from the Player class”?])

Answer 1

Well, you're using python in your example and so there are a few answers to this question. There is the OOP way of doing this and then there is the pythonic way of doing this.

The OOP way of doing this is that your __str__ (python's version of ToString ) would be abstract (or otherwise implemented generically) and you'd override that in the derived class. Though, truthfully, you'd not use ToString -- you'd define an abstract method for this purpose specifically. Perhaps PrintScore .

That said, your usage of OOP in this example isn't great either. Does the ComputerPlayer and HumanPlayer have different implementations resulting in the need of derived classes? Given your example (and perhaps you have plans for more), you don't. You could just use a Player Class and make a property " IsAI ". Set that for true for a computer player and false for human player.

I don't mean for this to sound critical so please don't take it that way. I simply mean to provide some guidance.