获取自身所有属性的字典，而不包括子类属性

Question

Say I have the following two classes:

class PlayerState:
    def __init__(self):
        self.someStateProp = 10

    # get the state of this class only as a dict
    def getState(self):
        return {name: attr for name, attr in self.__dict__.items()
                if not name.startswith("__")
                and not callable(attr)
                and not type(attr) is staticmethod}

class Player(PlayerState):
    def __init__(self):
        super().__init__()
        self.someNonStateProp = 'foo'

player = Player()
print(player.getState())
# someNonStateProp should not be shown
>> {'someStateProp': 10, 'someNonStateProp': 'foo'}

The method PlayerState.getState as it stands is able to return a dict containing all attributes of itself, excluding constructors and methods. I want to expand on it and make it also only return the direct properties of PlayerState , and not Player .

Edit: Using self.__class__.__dict__.items() instead of self.__dict__.items() just gives me all the methods of Player .

Answer 1

You provide no way to really differentiate between state and non-state attributes. If the object is mutable and has a mutable dict, there is really no way to determine who set the value for a particular attribute. There will be cases where children will want to add to the state. If the state is something special, keep it as a separate dictionary instead of filtering every time:

class PlayerState:
    def __init__(self):
        self.state = {}
        self.state['someProp'] = 10

    # get the state of this class only as a dict
    def getState(self):
        return self.state

class Player(PlayerState):
    def __init__(self):
        super().__init__()
        self.someNonStateProp = 'foo'
        self.state['otherProp'] = 'bar'

If it bothers you that you can't access state elements through normal dot access, add some properties to your class:

@property
def someStateProp(self):
    return self.state['someProp']

Alternatively, hard-code a list of the names you want.

class PlayerState:
    states = ['someStateProp']

    def __init__(self):
        self.someStateProp = 10

    # get the state of this class only as a dict
    def getState(self):
        return {name: getattr(self, name) for name in self.names}

class Player(PlayerState):
    names = PlayerState.names + ['otherStateProp']

    def __init__(self):
        super().__init__()
        self.someNonStateProp = 'foo'