Python call superclass constructor

Inheritance in Python

Inheritance in Python

1. What is Inheritance?
2. Advantages of Inheritance
3. Implementation of Inheritance in Python
4. Single Inheritance in Python
5. MultilevelInheritance
6. MultipleInheritance
7. What if both parent classes have a method with the same name?
8. Constructors inInheritance
9. Can we call super class constructor from child class constructor?

What is Inheritance in Python:

Inheritance, in general, is the passing of properties to someone. In programming languages, the concept of inheritance comes with classes.

1. Creating new classes from already existing classes is called inheritance.
2. The existing class is called a super class or base class or parent class.
3. The new class is called a subclass or derived class or child class.
4. Inheritance allows sub classes to inherit the variables, methods and constructors of their super class.

Advantages of Inheritance:

1. The main advantage of inheritance is code re-usability.
2. Time taken for application development will be less.
3. Redundancy (repetition) of the code can be reduced.

Implementation of Inheritance in Python:

While declaring subclass, we need to pass super class name into subclass’s parenthesis

Program: Implementing Inheritance (demo1.py)

class One: def m1(self): print("Parent class m1 method") class Two(One): def m2(self): print("Child class m2 method") c = Two() c.m1() c.m2()

Types of Inheritance in Python:

1. Single inheritance
2. Multilevel inheritance
3. Multiple inheritance

SINGLE INHERITANCE in PYTHON:

Creating a subclass or child class from a single superclass/parent class is called single inheritance. Diagrammatic representation of Python Single Inheritance is given below.

Program: Single Inheritance (demo2.py)

class A: def m1(self): print("A class m1 Method") class B(A): def m2(self): print("Child B is derived from A class: m2 Method") obj=B() obj.m1() obj.m2()

MULTILEVEL INHERITANCE in PYTHON:

If a class is derived from another derived class then it is called multi level inheritance. Diagrammatic representation of Python Multilevel Inheritance is given below.

Program: Multilevel inheritance (demo3.py)

class A: def m1(self): print("Parent class A: m1 Method") class B(A): def m2(self): print("Child class B derived from A: m2 Method") class C(B): def m3(self): print("Child class C derived from B: m3 Method") obj=C() obj.m1() obj.m2() obj.m3()

MULTIPLE INHERITANCE in PYTHON:

If a child class is derived from multiple superclasses then it is called multiple inheritance. Diagrammatic representation of Multiple Inheritance is given below.

Program: Multiple Inheritance (demo4.py)

class P1: def m1(self): print("Parent1 Method") class P2: def m2(self): print("Parent2 Method") class C(P1, P2): def m3(self): print("Child Method") c=C() c.m1() c.m2() c.m3()

What if both parent classes have a method with the same name?

There may be a chance that two parent classes can contain methods which are having the same method name in both classes. Syntactically this is valid.

Program: Parent classes having same method names (demo5.py)

class P1: def m1(self): print("Parent1 Method") class P2: def m1(self): print("Parent2 Method") class C(P1, P2): def m2(self): print("Child Method") c=C() c.m2()

Output:

In the above scenario, which method will child class inherit?

The answer for this depends on the order of inheritance of parent classes in the child class.

1. class C(P1, P2): ===>P1”s class method will be considered
2. class C(P2, P1): ===>P2”s class method will be considered

Program: demo5.py contd

class P1: def m1(self): print("Parent1 Method") class P2: def m1(self): print("Parent2 Method") class C(P1, P2): def m2(self): print("Child Method") c=C() c.m2() c.m1()

Program: Other scenario of demo5.py

class P1: def m1(self): print("Parent1 Method") class P2: def m1(self): print("Parent2 Method") class C(P2, P1): def m2(self): print("Child Method") c=C() c.m2() c.m1()

CONSTRUCTORS in INHERITANCE

By default, the super class‟s constructor will be available to the subclass.

Program:demo6.py

class A: def __init__(self): print("super class A constructor") class B(A): def m1(): print("Child Class B: m1 method from B") b=B()

Output:

If child class and super class both have constructors, then?

If child class and super class both have constructors, if you create an object to child class then child class constructor will be executed. While creating object for a class, that class’s constructor is first priority.

Program: demo7.py

class A: def __init__(self): print("super class A constructor") class B(A): def __init__(self): print("Child class B constructor") b=B()

Output:

Can we call super class constructor from child class constructor?

Yes, we can call super class constructor from child class constructor by using super() function. super() is a predefined function which is useful to call the superclass constructors, variables and methods from the child class.

Program: demo8.py

class A: def __init__(self): print("super class A constructor") class B(A): def __init__(self): print("Child class B constructor") super().__init__() b=B()

In the next article, I am going to discuss Method Resolution Order (MRO) in Python. Here, in this article, I try to explain Inheritance in Python with Examples. I hope you enjoy this Inheritance in Python with Examples article. I would like to have your feedback. Please post your feedback, question, or comments about this article.

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Python Super() Function: How to Call a Superclass Constructor

Learn how to call a superclass constructor using the super() function in Python. Discover the benefits, best practices, and tips for using super() effectively. Get started now.

• Understanding the super() function
• Calling superclass constructor using super()
• Python super function
• When to use super() in Python
• Advantages and disadvantages of using super() in Python
• Best practices and tips for using super() in Python
• Other code examples for calling superclass constructor using super() in Python
• Conclusion
• How do you call a super class init in Python?
• Do you need to call super init Python?
• How do you call a super method in Python?
• How do you call a superclass constructor in Python?

In Python, super() is a powerful function that allows a subclass to call a method from its parent or sibling class. The super() function can be used to give access to methods and properties of a parent or sibling class, making code more maintainable and extensible. In this blog post, we will discuss how to call a superclass constructor in Python using the super() function. We will explore the key points, important points, and helpful points related to this topic.

Understanding the super() function

The super() function in Python is used to call methods of a parent or sibling class. It returns a temporary object of the superclass that allows access to methods of the base class. It can be used to give access to methods and properties of a parent or sibling class. The super() function is a powerful tool for working with inheritance in Python.

Calling superclass constructor using super()

When overriding the __init__() method of a superclass, the __init__() method of the subclass must explicitly call the superclass __init__() method using super().__init__() . This ensures that the superclass constructor is called before the subclass constructor, and any properties or methods that need to be initialized in the superclass are properly set up.

In Python 2.x, the syntax for calling the superclass constructor using super() is super(, self) . This syntax is still valid in Python 3.x, but the preferred syntax is super().__init__() .

The super() method delegates method calls to a parent or sibling class of type. The super() method should be called before initializing any properties of the subclass. This ensures that the superclass constructor is called first, and any properties or methods that need to be initialized in the superclass are properly set up.

Python super function

When to use super() in Python

The super() method should be used in a collaborative manner among classes belonging to the same inheritance hierarchy. The super() method should be used when working with single inheritance. The super() method should be used when working with diamond inheritance to avoid method resolution order (MRO) issues. The super() method should be used when working with cooperative multiple inheritance.

Advantages and disadvantages of using super() in Python

Advantages:

• It makes code more maintainable and extensible.
• It reduces code duplication.
• It simplifies the code by abstracting the details of the inheritance hierarchy.

Disadvantages:

• It can be misused and lead to unexpected behavior.
• It can be difficult to understand and debug.
• It can be slower than direct method calls.

Best practices and tips for using super() in Python

• The super() method can be used to call other parent class methods besides the constructor.
• The super() method can be used in conjunction with the classmethod and staticmethod decorators.
• The super() method should be used to access inherited methods that have been overridden in a subclass.
• The super() method should be used to initialize data members of a subclass.
• The super() method can be used to access properties of a parent class.
• The super() method can be used to call a method in a sibling class.
• The super() method can be used to access methods of a grandparent class.

Other code examples for calling superclass constructor using super() in Python

In Python , for instance, python super init code sample

class test: def __init__(self, *args): print(f"called test with: ")class testing(test): def __init__(self, *args): print(f"Called testing with: ") super().__init__(*args) testing("hmm") # super is a keyword that calls the parent class 

class Square(Rectangle): def __init__(self, length): super().__init__(length, length)

In Python , python why call super(class).__init__()

super() lets you avoid referring to the base class explicitly, which can be nice. But the main advantage comes with multiple inheritance. Note that the syntax changed in Python 3.0: you can just say super().__init__() instead of super(ChildB, self).__init__() which IMO is quite a bit nicer. 

Conclusion

In conclusion, the super() function is an essential tool for calling methods of a parent or sibling class in Python. By following the best practices and tips discussed in this blog post, you can use super() effectively and avoid common pitfalls. We hope this post has been helpful in understanding how to call a superclass constructor using super() in Python.

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