Why less emphasis on private data?

[Thomas Ploch]

Paul Rubin schrieb:
> Thomas Ploch <Thomas.Ploch at gmx.net> writes:
>> Me neither, although I have to say that the '__' prefix comes pretty
>> close to being 'private' already. It depends on the definition of
>> private. For me, private means 'not accessible from outside the
>> module/class'.

> 
>     class A:
>       __x = 3
> 
>     class B(A):
>       __x = 4   # ok
> 
>     class C(B):
>       __x = 5   # oops!
> 
> Consider that the above three class definitions might be in separate
> files and you see how clumsy this gets.  


I don't understand why this should be oops, even if they are in
different files.

 >>> a = A()
 >>> print a._A__x
 3
 >>> b = B()
 >>> print b._B__x
 4
 >>> c = C()
 >>> print c._C__x
 5
 >>> dir(c)
 ['_A__x', '_B__x', '_C__x', '__doc__', '__module__']
 >>> print c._A__x
 3
 >>> print c._B__x
 4