In ES6, derived classes have to call super() if they have a constructor. In react, all components extend from the Component class. You don’t actually need a constructor for every ES6/react class. If no custom constructor is defined, it will use the default constructor. For base classes, it is: constructor() {} And for derived classes, … Read more
Not in this case. But in general, and especially when you use multiple inheritance, super() delegates to the next object in the Method Resolution Order (MRO) as is specified in the documentation: super([type[, object-or-type]]) Return a proxy object that delegates method calls to a parent or sibling class of type. This is useful for accessing … Read more
The two-argument form is only needed in Python 2. The reason is that self.__class__ always refers to the “leaf” class in the inheritance tree — that is, the most specific class of the object — but when you call super you need to tell it which implementation is currently being invoked, so it can invoke … Read more
super is a keyword in Java. It refers to the immediate parents property. super() //refers parent’s constructor super.getMusic(); //refers to the parent’s method – Read More on super
Are you reloading modules somehow in the middle of things? If so, that may explain this error. isinstance(self,DBAdminConnection) may become false after reloading modules because of the changes to memory references, apparently. Edit: if you’re running your web.py app under mod_wsgi, make sure you’re disabling autoreload: app = web.application(urls, globals(), autoreload=False)
You can, but you have to override __new__ which is called implicitly before __init__: class Z(X): def __new__(cls, a, b, c, d): self = super(Z, cls).__new__(cls, a, b, c) self.d = d return self >>> z = Z(1, 2, 3, 4) >>> z Z(a=1, b=2, c=3) >>> z.d 4 But d will be just an … Read more
Sometimes you need to validate the arguments before calling super(): class UpperBase(Base): def __init__(self, name): if not name_valid(name): raise ValueError() super(UpperBase, self).__init__(name) I don’t see why this wouldn’t be pythonic, because it’s the easiest way to do it and it’s straightforward. Also, read @JHSaunders’ comment, he makes a good point.
super() is not broken — it just should not be considered the standard way of calling a method of the base class. This did not change with Python 3.x. The only thing that changed is that you don’t need to pass the arguments self, cls in the standard case that self is the first parameter … Read more
super Essentially, it allows you to use the implementations of the current class’ superclass. For the gritty details of the Objective-C runtime: [super message] has the following meaning: When it encounters a method call, the compiler generates a call to one of the functions objc_msgSend, objc_msgSend_stret, objc_msgSendSuper, or objc_msgSendSuper_stret. Messages sent to an object’s superclass … Read more
No you cannot. The super() call needs to know what class the method is part of, to search the base classes for an overridden method. If you pass in self.__class__ (or better still, type(self)) then super() is given the wrong starting point to search for methods, and will end up calling its own method again. … Read more