子类属性不同

Question

我希望子类的属性与父类的同一属性具有不同的名称，即使它的含义相同。例如，父类是属性为“height”的Shape，子类是属性为“Diameter”的Circle。下面是对我当前拥有的内容的简化，但是我希望Circle类使用“diameter”而不是“height”。处理这个问题最好的方法是什么？你知道吗

注意：我将继承另一个类中的Circle，该类也需要使用“diameter”而不是“height”。谢谢您！你知道吗

class Shape():
    def __init__(self, shape, bar_args, height):
        self.shape = shape
        self.height = height
        etc.

class Circle(Shape):
    def __init__(self, height, foo_args, shape='circle'):
    Shape.__init__(self, shape, height)
        self.height = height
        etc.

Answer 1

您可以定义一个property来访问读写访问的原始属性：

class Circle(Shape):
    def __init__(self, height, foo_args, shape='circle'):
        Shape.__init__(self, shape, height) # assigns the attributes there
        # other assignments
    @property
    def diameter(self):
        """The diameter property maps everything to the height attribute."""
        return self.height
    @diameter.setter
    def diameter(self, new_value):
        self.height = new_value
    # deleter is not needed, as we don't want to delete this.

如果您经常需要这种行为，并且您发现setter和getter的属性处理太不方便，那么您可以更进一步build您自己的descriptor class：

class AttrMap(object):
    def __init__(self, name):
        self.name = name
    def __get__(self, obj, typ):
        # Read access to obj's attribute.
        if obj is None:
            # access to class -> return descriptor object.
            return self
        return getattr(obj, self.name)
    def __set__(self, obj, value):
        return setattr(obj, self.name, value)
    def __delete__(self, obj):
        return delattr(obj, self.name)

有了这个，你就可以

class Circle(Shape):
    diameter = AttrMap('height')
    def __init__(self, height, foo_args, shape='circle'):
        Shape.__init__(self, shape, height) # assigns the attributes there
        # other assignments

而diameter描述符将把对它的所有访问重定向到命名属性（这里：height）。你知道吗