Python: get only classes defined in imported module with dir()?

Question

I've got a module written in Python. I now want to import it into another script and list all classes I defined in this module. So I try:

>>> import my_module
>>> dir(my_module)
['BooleanField', 'CharField', 'DateTimeField', 'DecimalField', 'MyClass', 'MySecondClass', 'ForeignKeyField', 'HStoreField', 'IntegerField', 'JSONField', 'TextField', '__builtins__', '__doc__', '__file__', '__name__', '__package__', 'datetime', 'db', 'division', 'os', 'struct', 'uuid']

The only two classes which I defined in my_module are MyClass and MySecondClass, the other stuff are all things that I imported into my_module.

I now want to somehow be able to get a list of all classes which are defined in my_module without getting all the other stuff. Is there a way to do this in Python?

While it is possible to get this information, trying to do so is fragile and results in unobvious behaviour. In general, reflection is very useful for debugging, but should be considered very carefully before being used in actual production code. — Sven Marnach
– Sven Marnach, Commented Mar 22, 2014 at 14:13
To document which names may be used outside (public), you could define __all__ attribute: [cls for name in your_module.__all__ for cls in [getattr(your_module, name)] if inspect.isclass(cls)] it works even if the class is defined in a submodule but you want it to be available from toplevel module. Try it with asyncio module, to see what I mean — jfs
– jfs, Commented Mar 24, 2014 at 6:58

anon582847382 · Accepted Answer · 2014-03-22 14:24:43Z

51

Use the inspect module to inspect live objects:

>>> import inspect
>>> import my_module
>>> [m[0] for m in inspect.getmembers(my_module, inspect.isclass) if m[1].__module__ == 'my_module']

That should then work, getting every class defined within that my_module.

edited Mar 22, 2014 at 14:24

answered Mar 22, 2014 at 14:02

anon582847382

20.5k5 gold badges58 silver badges60 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Matt Hancock Over a year ago

Nice. Probably if m[1].__module__ == my_module.__name__ would be nicer.

Most Wanted · Accepted Answer · 2016-03-14 16:51:35Z

8

You can use Python Class Browser

import pyclbr
module_name = 'your_module'
module_info = pyclbr.readmodule(module_name)
print(module_info)

for item in module_info.values():
    print(item.name)

it will list all classes defined in your_module

answered Mar 14, 2016 at 16:51

Most Wanted

7,2498 gold badges64 silver badges82 bronze badges

2 Comments

Alexis.Rolland Over a year ago

Nice, is this module installed with Python by default or does it require to be installed manually?

Most Wanted Over a year ago

@Alexis.Rolland it's from standard library

Community · Accepted Answer · 2017-05-23 12:10:25Z

1

If you really want to use dir(), here it is:

>>> import module
>>> [eval("module." + objname) for objname in dir(module) if type(eval("module." + objname)) is type]

or (script form)

import module
classes = []
for objname in dir(module):
    obj = eval("module." + objname)
    if type(obj) is type:
        classes.append(obj)
print(classes)

But this uses the "eval" function, and is really not safe for use. I'd stick to the chosen answer

edited May 23, 2017 at 12:10

CommunityBot

11 silver badge

answered Apr 5, 2017 at 10:10

Epic Wink

86514 silver badges22 bronze badges

Collectives™ on Stack Overflow

Python: get only classes defined in imported module with dir()?

3 Answers 3

1 Comment

2 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related