On 2017-02-22 20:53, boB Stepp wrote:
On Wed, Feb 22, 2017 at 10:25 PM, boB Stepp <robertvst...@gmail.com>
wrote:
I am trying to wrap my head around the mechanics of inheritance in
Python 3. I thought that all attributes of a superclass were
accessible to an instance of a subclass. But when I try the
following:
py3: class A:
... def __init__(self):
... self.aa = 'class A'
...
py3: class B(A):
... def __init__(self):
... self.bb = 'class B'
...
py3: a = A()
py3: b = B()
py3: b.aa
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'B' object has no attribute 'aa'
I am unsuccessful...
The 'attribute(s)' to which you refer only exist because of the
__init__s.
B's __init__ over rides that of A so A's __init__ never gets called
during instantiation of b and hence b.aa never comes into being.
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