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The wonders of cooperative inheritance, or using super in Python 3. It mentions the useful method mro() that shows you the method resolution order. In your second example, where you call super in A, the super call continues on in MRO. The next class in the order is B, this is why B's init is called the first time.
Nov 28, 2013 · Python mangles these names with the class name: if class Foo has an attribute named __a, it cannot be accessed by Foo.__a. (An insistent user could still gain access by calling Foo._Foo__a .) Generally, double leading underscores should be used only to avoid name conflicts with attributes in classes designed to be subclassed.
Jan 31, 2020 · 1. Essentially, there are two things you need to do to make your __init__ methods play nice with multiple inheritance in Python: Always take a **kwargs parameter, and always call super().__init__(**kwargs), even if you think you are the base class. Just because your superclass is object doesn't mean you are last (before object) in the method ...
The design of multiple inheritance is really really bad in python. The base classes almost need to know who is going to derive it, and how many other base classes the derived will derive, and in what order... otherwise super will either fail to run (because of parameter mismatch), or it will not call few of the bases (because you didn't write super in one of the base which breaks the link)!
There is such a design choice as Inheritance vs Composition which actually may be particularly interesting for Python, but it mainly asks whether you want to reuse code by copying the behavior of a standalone parent class (inheritance) or you want to separate different class behavior granules (for lack of better word) and then create classes ...
Dec 17, 2013 · By "modern Python" I mean something that will run in Python 2.5 but be 'correct' for the Python 2.6 and Python 3.* way of doing things. And by "custom" I mean an Exception object that can include extra data about the cause of the error: a string, maybe also some other arbitrary object relevant to the exception.
May 22, 2023 · This will handle all multiple inheritance correctly. (When you have a multiple inheritance tree in Python, a method resolution order is generated and the lookups go through parent classes in this order.) Take care: there are many places to get confused about multiple inheritance in Python. You might want to read super() Considered Harmful. If ...
Adam's has the benefit of showing both Python2 and Python3 forms. While this example works with both versions, the "new-style class" business and the arguments to super() are artifacts of Python2 - see Adam's Python 3 version for cleaner code example (in Python3, all classes are now new-style classes, so there is no need to explicitly inherit from object, and super() does not require the class and self arguments, it's just super()).
Oct 25, 2010 · class <ClassName>(superclass): #code follows. In the absence of any other superclasses that you specifically want to inherit from, the superclass should always be object, which is the root of all classes in Python. object is technically the root of "new-style" classes in Python.
This is a decent enough solution which works with python 2.4+, but I like the solution I found on geek at play better, as it doesn't require re-creating the property in the subclass -- just the getter or setter method can be overridden, and normal MRO applies.
