How to change parent attribute in subclass python
You ask two questions:
How it should be done in Python?
class Bar(Foo): data = Foo.data + "def"Am i wrong by design?
I generally don't use class variables in Python. A more typical paradigm is to initialize an instance variable:
>>> class Foo(object):... data = "abc"... >>> class Bar(Foo):... def __init__(self):... super(Bar, self).__init__()... self.data += "def"... >>> b = Bar()>>> b.data'abcdef'>>>
You can initialize the state of the Foo class from the Bar class and then append to the data like so:
class Foo(object): def __init__(self): self.data = "abc"class Bar(Foo): def __init__(self): super(Bar, self).__init__() self.data += "def"When you instantiate an instance of Bar, the value of data that results is:
abcdef
You can refer to class variables of Foo from Bar's namespace via regular attribute access:
class Bar(Foo): data = Foo.data + 'def'I don't know if it's a good practice, but there's no reason for it to be bad.