It can be tough trying to debug classes, inherited classes, class methods etc in general. Here’s 2 useful debugging utility functions i love to use to sort through the mess.
1. Printing attributes and values
def print_attr(obj): """ Traverses the items in the object's dictionary and prints each attribute name and its corresponding value. """ for attr in obj.__dict__: print attr, getattr(obj, attr)
As explained in docstring, function print_attr() takes in an object and spits out each of its attributes and its corresponding value.
The built-in function getattr() takes an object and an attribute name(as string) and returns the attribute’s value.
2. Find defining class
def find_defining_class(obj, method_name): """ Uses method resolution method(MRO) to get the list of class objects(types) that will be searched for methods. Return the class to which the method 'method_name' belong to. """ for origin in type(obj).mro(): if method_name in origin.__dict__: return origin
Useful if your class belongs to a long chain of super classes and you are trying to find out which class does a particular method belong to. This method works because of Method Resolution Order rule in python.
Here’s an example:
>>> hand = Hand() >>> print find_defining_class(hand, 'shuffle) <class 'Card.Deck'>
So the shuffle method for this Hang object is the one in Deck.
Hope this 2 utility debugging functions can save you time traversing those pesky bugs. Please share your secret debugging functions too!
Happy debugging! Ok fine, that’s a fallacy…Don’t die debugging!