Question

How can I know which members module/package defines? By defining I mean:

somemodule.py

import os # <-- Not defined in this module
from os.path import sep # <-- Not defined in this module

I_AM_ATTRIBUTE = None # <-- Is defined in this module

class SomeClass(object): # <-- Is defined also...
    pass

So I need a some sort of function that when called would yield only I_AM_ATTRIBUTE and SomeClass.

Now I have been trying to do using dir(somemodule), but how can I know which ones are defined in somemodule? Checking against __module__ does not work, since that is not defined in modules and attributes (such as os package, or sep attribute).

Apparently wild import (from somemodule import *) also fails to filter those, so is it even possible?

Best I can get is:

import somemodule

for name in dir(somemodule):
    try:
        value = getattr(somemodule, name)
    except:
        pass
    else:
        if hasattr(value, "__module__"):
            if value.__module__ != somemodule.__name__:
                continue
        if hasattr(value, "__name__"):
            if not value.__name__.startswith(__name__):
                continue
        print "somemodule defines:", name

Takes os out, but leaves sep.

Answer 1

What does “define” mean? For me, defined means that some symbol is part of the module’s public interface. This matches up with how it seems you’re trying to use the term, including in your example, but if you have some purpose which doesn’t align with this definition, you’ll have to clarify the question on what you’re really trying to do. This makes it a documentation issue.

So you can’t know what a module defines, and some things which are imported might still be “defined in that module” or “defined to be part of that module’s public interface”. This happens often when importing from a private module, including C extension modules.

For your own modules, use __all__ (can do that easily) or the informal underscore prefix for non-public (e.g. _private_var = 42). Both conventions are recognized by help() and should be used by other documentation generators.