Problem: IPython's autoreload and superreload may reload modules such that obj=Obj() -> edit file & save -> isinstance(obj, Obj) == False. Sometimes even imp.reload of all involved modules doesn't absolve it.

Goal: a method with a 'fallback' on looser criterion that are as close to isinstance as possible.


def isinstance_ipython(obj, ref_class):
    def _class_name(obj):
        name = getattr(obj, '__qualname__', getattr(obj, '__name__', ''))
        return (getattr(obj, '__module__', '') + '.' + name).lstrip('.')
    return (isinstance(obj, ref_class) or 
            _class_name(type(obj)) == _class_name(ref_class))

obj is always instance of a class, and ref_class is always a Python 3.x, non-builtin class. __qualname__ and __module__ are included to prefer longest possible name, but fallback upon shorter names via empty strings.

Any improvements to reliability of this method (i.e. reduced false positives/negatives)? Not interested in speed or readability, but they're welcome as bonus.



Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.