instantiate all subclasses of a class

[Simon Forman]

Daniel Nogradi wrote:
> What is the simplest way to instantiate all classes that are
> subclasses of a given class in a module?
>
> More precisely I have a module m with some content:
>
> # m.py
> class A:
>     pass
> class x( A ):
>     pass
> class y( A ):
>     pass
> # all kinds of other objects follow
> # end of m.py
>
> and then in another module I have currently:
>
> # n.py
> import m
> x = m.x( )
> y = m.y( )
> # end of n.py
>
> and would like to automate this in a way that results in having
> instances of classes from m in n whose names are the same as the
> classes themselves. But I only would like to do this with classes that
> are subclasses of A.
>
> Any ideas?

It's pretty easy


import m
from inspect import getmembers, isclass, getmro

t = '%s = m.%s()'

for name, class_ in getmembers(m, isclass):
    if class_ is m.A:
        continue
    if m.A in getmro(class_):
        exec t % (name, name)


Peace,
~Simon