Question

I have a base class with a property which (the get method) I want to overwrite in the subclass. My first thought was something like:

class Foo(object):     def _get_age(self):         return 11      age = property(_get_age)   class Bar(Foo):     def _get_age(self):         return 44 

This does not work (subclass bar.age returns 11). I found a solution with an lambda expression which works:

age = property(lambda self: self._get_age()) 

So is this the right solution for using properties and overwrite them in a subclass, or are there other preferred ways to do this?

Answer 1

I simply prefer to repeat the property() as well as you will repeat the @classmethod decorator when overriding a class method.

While this seems very verbose, at least for Python standards, you may notice:

1) for read only properties, property can be used as a decorator:

class Foo(object):     @property     def age(self):         return 11  class Bar(Foo):     @property     def age(self):         return 44 

2) in Python 2.6, properties grew a pair of methods setter and deleter which can be used to apply to general properties the shortcut already available for read-only ones:

class C(object):     @property     def x(self):         return self._x      @x.setter     def x(self, value):         self._x = value