How to convert a string containing a path and access the class using that string in Python?

Question

I'm looking to take in a string of the format "package.file.module.classname" and use that to access the docstring of the particular class or functions within.

I can import the initial package, but the remaining part of the path remains flexible to any input.

I've attempted using getattr(sys.modules[__name__], classname) but that seems to be limited to within a current package and cannot be extended outside it

Answer 1

After parsing the string into module and class names, I think you need to use importlib to import the module, then use getattr to get the class object from the module by name.

After that, I was able to get docstrings using inspect

Here's an example: Say you have a birds module: animals/birds.py:

class Duck:
    """
    A duck class
    """
    def __init__(self, name):
        self._name = name

    def quack(self):
        """
        A quack method
        """
        print(f"{self._name} is quacking")

This code will return a dict with class and method names as keys, and their docstrings as values:

import importlib
import inspect


def get_docstrings(class_string):
    try:
        # Split the string into module, class name parts
        path_parts = class_string.split('.')
        module_name = '.'.join(path_parts[:-1])
        class_name = path_parts[-1]
        module = importlib.import_module(module_name)

        # Retrieve the class object from the module
        class_obj = getattr(module, class_name)

        doc_strings = {}

        # Return the docstring of the class
        doc_strings[class_name] = class_obj.__doc__

        for name, member in inspect.getmembers(class_obj):
            if inspect.isfunction(member):
                doc_strings[name] = member.__doc__

        return doc_strings

    except (AttributeError, ImportError, IndexError):
        return None

# Example usage
docstring = get_docstrings("animals.birds.Duck")

Note that docstrings will have new line escapes and other formatting:

{
  'Duck': '\n    A duck class\n    ',
  '__init__': None,
  'quack': '\n        A quack method\n        '
}