使用Python重写属性

Question

在Python中，怎么重写一个属性的获取方法（getter）呢？

我试过这样做：

class Vehicule(object):

    def _getSpatials(self):
        pass

    def _setSpatials(self, newSpatials):
        pass

    spatials = property(_getSpatials, _setSpatials)

class Car(Vehicule)

    def _getSpatials(self):
        spatials = super(Car, self).spatials()
        return spatials

但是获取方法却调用了Vehicule类的方法，而不是Car类的方法。

我应该怎么改呢？

Answer 1

这可能会对你有帮助：Python中的属性和继承

Answer 2

看起来你想让汽车（Car）的空间属性的获取方法去调用车辆（Vehicule）的空间属性的获取方法。你可以这样做：

class Vehicule(object):
    def __init__(self):
        self._spatials = 1
    def _getSpatials(self):
        print("Calling Vehicule's spatials getter")
        return self._spatials
    def _setSpatials(self,value):
        print("Calling Vehicule's spatials setter")        
        self._spatials=value
    spatials=property(_getSpatials,_setSpatials)

class Car(Vehicule):
    def __init__(self):
        super(Car,self).__init__()
    def _getSpatials(self):
        print("Calling Car's spatials getter")
        return super(Car,self).spatials
    spatials=property(_getSpatials)

v=Vehicule()
c=Car()
print(c.spatials)
# Calling Car's spatials getter
# Calling Vehicule's spatials getter
# 1

另一方面，从汽车的设置方法中调用车辆的设置方法就比较复杂了。直接的方法是行不通的：

class Car(Vehicule):
    def __init__(self):
        super(Car,self).__init__()
    def _getSpatials(self):
        print("Calling Car's spatials getter")
        return super(Car,self).spatials
    def _setSpatials(self,value):
        print("Calling Car's spatials setter")
        super(Car,self).spatials=value
    spatials=property(_getSpatials,_setSpatials)

v=Vehicule()
c=Car()
print(c.spatials)
c.spatials = 10
AttributeError: 'super' object has no attribute 'spatials'

相反，诀窍是调用 super(Car,self)._setSpatials：

class Car(Vehicule):
    def __init__(self):
        super(Car,self).__init__()
    def _getSpatials(self):
        print("Calling Car's spatials getter")
        return super(Car,self).spatials
    def _setSpatials(self,value):
        print("Calling Car's spatials setter")
        super(Car,self)._setSpatials(value)
    spatials=property(_getSpatials,_setSpatials)

v=Vehicule()
c=Car()
print(c.spatials)
# Calling Car's spatials getter
# Calling Vehicule's spatials getter
# 1
c.spatials = 10
# Calling Car's spatials setter
# Calling Vehicule's spatials setter
print(c.spatials)
# Calling Car's spatials getter
# Calling Vehicule's spatials getter
# 10