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I'm changing some classes of mine from an extensive use of getters and setters to a more pythonic use of properties.
But now I'm stuck because some of my previous getters or setters would call the corresponding method of the base class, and then perform something else. But how can this be accomplished with properties? How to call the property getter or setter in the parent class?
Of course just calling the attribute itself gives infinite recursion.
class Foo(object): @property def bar(self): return 5 @bar.setter def bar(self, a): print a class FooBar(Foo): @property def bar(self): # return the same value # as in the base class return self.bar # --> recursion! @bar.setter def bar(self, c): # perform the same action # as in the base class self.bar = c # --> recursion! # then do something else print 'something else' fb = FooBar() fb.bar = 7 
425
// As base-class pointer cannot access the derived class variable.
An overriding property declaration must specify exactly the same access modifier, type, and name as the inherited property. Beginning with C# 9.0, read-only overriding properties support covariant return types. The overridden property must be virtual , abstract , or override .
Overriding Properties in C#We can also override the property of a parent class from its child class similar to a method. Like methods, we need to use virtual keyword with the property in the parent class and override keyword with the porperty in the child class.
You can create a property by calling property() with an appropriate set of arguments and assigning its return value to a class attribute. All the arguments to property() are optional. However, you typically provide at least a setter function.
You might think you could call the base class function which is called by property:
class FooBar(Foo): @property def bar(self): # return the same value # as in the base class return Foo.bar(self) Though this is the most obvious thing to try I think - it does not work because bar is a property, not a callable.
But a property is just an object, with a getter method to find the corresponding attribute:
class FooBar(Foo): @property def bar(self): # return the same value # as in the base class return Foo.bar.fget(self) super() should do the trick:
return super().bar In Python 2.x you need to use the more verbose syntax:
return super(FooBar, self).bar If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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