Examining the __init__() and super() methods in Python

Getting Started with Python's super()

The super() function in Python's object-oriented programming is sometimes a source of confusion for newcomers. This powerful function is mostly used to verify that base classes' __init__() methods are correctly invoked, resulting in a more manageable and scalable code structure.

In this article, we'll look at the differences between utilizing Base.__init__() and super().__init__(), and see why super() is typically the recommended method. We'll also share code examples to put these concepts into practice.

Command	Description
Base.__init__(self)	It directly invokes the base class's __init__ function. Used to guarantee that the base class is correctly initialized.
super(ChildB, self).__init__()	The super() function calls the underlying class's __init__ method. This is the preferred way to initialize base classes.
print("Base created")	Prints a message to the console. Used to debug and ensure that the base class has been initialized.
print("ChildA created")	Prints a message to the console. Used to confirm that ChildA was created and initialized.
print("ChildB created")	Prints a message to the console. Used to confirm that ChildB was created and initialized.
print("Derived class with Base.__init__")	Prints a message stating that the Derived class was initialized with Base.__init__.
print("Derived class with super().__init__")	Prints a message stating that the Derived class was initialized with super().__init__.

An in-depth explanation of Python's super() usage

The preceding programs demonstrate the use of and in Python to establish base classes inside a class hierarchy. In the original script, we define a base class named with a __init__() function that outputs "Base created" when an instance of the class is initialized. We then create two derived classes, and . To ensure appropriate initialization of the base class, explicitly calls the Base.__init__(self) method within its own method. This strategy is simple, but it can be inefficient if there are several base classes or complex inheritance structures.

In , the approach is utilized instead. Python's function offers a more flexible and maintainable approach to call base class methods, particularly in multiple inheritance contexts. It automatically resolves the methods to be called in the correct sequence, according to the method resolution order (MRO). This not only simplifies the code, but also improves its robustness and adaptability to changes in the class hierarchy. The second script expands on these notions by contrasting the direct use of Base.__init__() and functions, demonstrating how each influences the initialization process.

class Base(object):
    def __init__(self):
        print("Base created")

class ChildA(Base):
    def __init__(self):
        Base.__init__(self)
        print("ChildA created")

class ChildB(Base):
    def __init__(self):
        super(ChildB, self).__init__()
        print("ChildB created")

ChildA()
ChildB()

class Base:
    def __init__(self):
        print("Base class initialized")

class DerivedWithBaseInit(Base):
    def __init__(self):
        Base.__init__(self)
        print("Derived class with Base.__init__")

class DerivedWithSuperInit(Base):
    def __init__(self):
        super().__init__()
        print("Derived class with super().__init__")

print("Creating DerivedWithBaseInit:")
derived1 = DerivedWithBaseInit()

print("Creating DerivedWithSuperInit:")
derived2 = DerivedWithSuperInit()

Dive further into Python's super() function.

The preceding explanations focused on the fundamental usage of and . It's vital to grasp the advanced characteristics and benefits of using . One significant advantage is compatibility with multiple inheritance. In a complex class hierarchy where a class may inherit from several base classes, utilizing super() ensures that all base classes are appropriately initialized according to the method resolution order (MRO). This avoids potential situations in which a base class is initialized several times or not at all.

Improved code readability and maintainability are also important considerations. Using requires the programmer to explicitly name the base class, which limits the code's flexibility. If the base class name or inheritance structure changes, all direct calls to must be modified. In contrast, removes the base class name, making the code more responsive to modifications. This abstraction is also consistent with the notions of polymorphism and encapsulation, which are fundamental to object-oriented programming.

Using in Python provides proper initialization of base classes while also enhancing code flexibility and maintainability. It is especially useful in many inheritance contexts, where straight calls to base class functions can be laborious and error-prone. By abstracting the base class names, enables cleaner and more flexible code. Writing strong object-oriented Python code requires understanding the differences between and Base.__init__().