nested classes

Steve Holden steve at
Fri Mar 20 19:35:11 CET 2009

Benjamin Kaplan wrote:
> On Fri, Mar 20, 2009 at 10:06 AM, Esmail <ebonak at
> <mailto:ebonak at>> wrote:
>     Hello all,
>     I am curious why nested classes don't seem to be used much in Python.
>     I see them as a great way to encapsulate related information, which is
>     a
>     good thing.
>     In my other post "improve this newbie code/nested functions in
>     Python?"
>     (I accidentally referred to nested functions rather nested classes -
>     it was late)
>     I asked something similar in the context of a specific example where I
>     think the
>     use of nested classes makes sense.
>     But perhaps not?
> Nested classes in Python don't add much other than an additional level
> of complexity (and an extra hash lookup). Behavior in python is usually
> grouped into modules, not into classes. The only reason to nest a class
> in Python is if the first class is going to generate the second class on
> the fly.
And even then you;d nest it inside a method of the class.

Steve Holden           +1 571 484 6266   +1 800 494 3119
Holden Web LLC       
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