Why does calling Python’s ‘magic method’ not do type conversion like it would for the corresponding operator?

a – b isn’t just a.__sub__(b). It also tries b.__rsub__(a) if a can’t handle the operation, and in the 1 – 2. case, it’s the float’s __rsub__ that handles the operation. >>> (2.).__rsub__(1) -1.0 You ran a.__rsub__(2.), but that’s the wrong __rsub__. You need the right-side operand’s __rsub__, not the left-side operand. There is no … Read more

__new__ method giving error object.__new__() takes exactly one argument (the type to instantiate)

instance = super(Foo, cls).__new__(cls,*args, **kwargs) is correct. However, you are responsible for first removing arguments that your class introduces, so that when object.__new__ is ultimately called, both *args and **kwargs are empty. Your code should be something like class Foo: def __new__(cls, a, b, *args, **kwargs): print(“Creating Instance”) instance = super(Foo, cls).__new__(cls, *args, **kwargs) return … Read more

Use of PHP Magic Methods __sleep and __wakeup

As already described, __sleep() is called when you serialize() an object and __wakeup() after you unserialize() it. Serialization is used to persist objects: You will get a representation of an object as a string that can then be stored in $_SESSION, a database, cookies or anywhere else you desire. Resource values However, serialize() cannot serialize … Read more