Enumerating Classes in Modules

[Rob Snyder]

Jeff Shannon wrote:

> Rob Snyder wrote:
> 
>>Greetings -
>>
>>I have a situation where I need to be able to have a Python function that
>>will take all the modules in a given directory and find all the classes
>>defined in these modules by name. Ultimately, I would need to loop through
>>all of these, instantiating each of the classes in turn and calling a
>>pre-known method of each.
>>
>>Finding the name of each module is not a problem, but loading the classes
>>out the module once I know the name is where I'm lost.
>>  
>>
> 
> Hm.  Any reason to not simply import the module (using the __import__()
> function), going through all names in that module's namespace, and
> attempting to call the method on them?  (Catching AttributeErrors as
> necessary, of course.)
> 
> Something like this (untested, unresearched, and totally off the top of
> my head):
> 
> for modname in nameslist:
>     plugins[modname] = __import__(modname)
>     # ....
>     for item in dir(plugins[modname]):
>         try:
>             item.standard_method()
>         except AttributeError:
>             pass
> 
> If you need something a bit more specific, maybe you could require all
> plugin classes to be derived from a common subclass, and before calling
> the standard_method() you could check issubclass(item, plugin_base)...
> 
> Jeff Shannon
> Technician/Programmer
> Credit International

Any reason no to? Not other then I couldn't figure it out on my own. :) 

Thanks so much for your help, this will do the trick nicely.

Rob Snyder