Your question is a little bit vague, and lacks important details, like the error you're getting, and a bit more context regarding your actual goals here. Having said that, I've noticed a couple of things that might be the cause of the problems you're having:
BaseClass.__subclasses__ is a method, therefore, you need to call it instead of accessing it, like you access a class property, or attribute. To do so, use BaseClass.__subclasses__() instead.- In order to your
get_subclasses() function to work, you need to first import the subclasses. Otherwise python won't know which classes inherit from BaseClass.
Corrected code
Here's the correct implementation of get_subclasses() function, as mentioned above:
from basemodule import BaseClass
def get_subclasses():
"""Get subclasses from `basemodule.BaseClass`."""
for cls in list(BaseClass.__subclasses__()):
# call subclasses here
print(cls.__name__) # Added print statement to test the solution.
Example
Without importing module1, and module2
Here's an example of the output from get_subclasses() I receive, when I don't import the modules that host the subclasses:
Importing module1, and module2
When I import both modules that host the subclasses, you then get the output I think you're expecting:
Full-code
Here's the full code of the examples:
# my_pckg/basemodule.py
from abc import ABCMeta, abstractmethod
class BaseClass(object):
@abstractmethod
def method(self, inputs=None):
pass
# ================================================
# my_pckg/module1.py
from my_pckg.basemodule import BaseClass
class derivedClass1(BaseClass):
def __init__(self):
super().__init__()
def method(self, inputs):
# method implemented in derivedClass1
pass
# ================================================
# my_pckg/module2.py
from my_pckg.basemodule import BaseClass
class derivedClass2(BaseClass):
def __init__(self):
super().__init__()
def method(self, inputs):
# method implemented in derivedClass2
pass
# ================================================
# my_pckg/test.ipynb
from basemodule import BaseClass
from module1 import *
from module2 import *
def get_subclasses():
"""Get subclasses from `basemodule.BaseClass`."""
for cls in list(BaseClass.__subclasses__()):
# call subclasses here
print(cls.__name__) # Added print statement to test the solution.
get_subclasses()
# Prints:
# derivedClass1
# derivedClass2
Important notes
The imports as shown in the example pictures won't work, if you're trying to use them from outside the parent module. In the example I just gave, here's the complete tree view of the entire package structure:
my_pckg
|______init__.py # <-- Needed to make my_pckg submodules "importable".
|____basemodule.py # <-- Hosts the BaseClass class.
|____module1.py # <-- Hosts the derivedClass1 subclass.
|____module2.py # <-- Hosts the derivedClass2 subclass.
|____Test.ipynb # <-- Where the test from the screenshots took place.
If you want to import these modules from outside the package you have two options:
- Create a setup for you package, and
pip install it (use the -e flag to install it in development mode).
- Import
sys, and add my_pckg path to the known paths.
import sys
sys.path.insert(0, './my_pckg')
from basemodule import BaseClass
from module1 import *
from module2 import *
def get_subclasses():
"""Get subclasses from `basemodule.BaseClass`."""
for cls in list(BaseClass.__subclasses__()):
# call subclasses here
print(cls.__name__) # Added print statement to test the solution.
get_subclasses()
# Prints:
# derivedClass1
# derivedClass2
For example:
Circular Imports
Do NOT import module1, and module2 inside basemodule, as this leads to a circular import. This happens because when you import basemodule, python will see that the module needs to import module1, and module2 and therefore goes to these modules. There, it finds out that both actually require basemodule themselves, so it goes back to basemodule. You can see that this becomes an infinite circle, where no module is able to be imported. To overcome this, place get_subclasses() function in a separate module, alongside all your necessary imports, like the example pictures.
