Working on classes for a text based game in python

问题

i'm trying to create a function to raise max hp whenever a stat is increased or decreased. i have tried changing self.maxHpCalc() player.** moving the variables = (int) into the orc class in every why i can think of and have been having no luck. depending on how i change it i get self/player have no attribute strength, maxHp or maxHpCalc is not defined.

class player:
    def __init__(self, hp = 1 , maxHp = 1, strength = 4, defense = 5):
        self.hp = hp
        self.maxHp = maxHpCalc()
        self.strength = strength
        self.defense = defense

    def maxHpCalc():
        player.maxHp = player.strength + player.defense

class orc(player):
    def __init__(self, hp, maxHp, strength , defnese):
        super().__init__(hp, maxHp, strength, defense)
print(player.maxHp)

everything i change give me player/self has no attribute strength at the moment

回答1:

Here's some fixed code, with a small driver program to exercise the classes.

Note the following changes

1. The function maxHpCalc should be a bound method, if it is to operate on data contained in a player instance. Therefore it should have a self parameter and should reference strength and defense from that self reference.
2. When calling _maxHpCalc you should reference self. I made it a bound method and it needs an instance to work on. I added an underscore to indicate it's a private method.
3. You should call maxHpCalc after setting the values of strength and defense, otherwise they are not defined at the point the function is called.
4. player.maxHp makes no sense. player is a class and has no static property maxHp, you need an instance to access that property. I create an instance and reference that.

code:

class player:
    def __init__(self, hp=1, maxHp=1, strength=4, defense=5):
        self.hp = hp
        self.strength = strength
        self.defense = defense
        self.maxHp = self._maxHpCalc()

    def _maxHpCalc(self):
        return self.strength + self.defense

class orc(player):
    def __init__(self, hp, maxHp, strength , defense):
        super().__init__(hp, maxHp, strength, defense)

p = player()
o = orc(1,2,3,4)

print(p.maxHp)
print(o.maxHp)

I also have to ask, why include a constructor parameter maxHp if you don't use it but calculate it from other parameters?

来源：https://stackoverflow.com/questions/43482829/working-on-classes-for-a-text-based-game-in-python