Object-Oriented Programming.
In the current era, proficiency in Object-Oriented Programming(OOP) concepts is non-negotiable for software developers. Whether you're crafting web apps, mobile solutions, desktop software, or even embedded systems, OOP forms the backbone of scalable, maintainable, and extensible software.
Most Employers, are on the lookout for candidates who not only understand OOP principles but also have hands-on-experience applying them. Wondering Why? Because OOP facilitates modular, reusable code, simplifies system complexity through abstraction, ensures code reliability & security via encapsulation, and enables flexibility through inheritance and polymorphism.
In a nutshell, if you're serious and passionate about career in tech and software development, understanding and mastering OOP is a must. It's the key to unlock opportunities and standing out in a competitive job market.
Basic Concepts in a simple and easy-to-understand way :
Encapsulation : Encapsulation is like putting things in a box and only allowing certain actions to happen from the outside. In OOP, this means, bundling together the attributes and the methods that operate on the data within a class. This helps to keep the code organized and prevents outside interference.
Classes : A class acts as a blueprint or template for creating an object. It define what an object will be capable of and what it will look like.
In python, "class" keyword is used to define a new class.
Pass statement: The pass statement is a null operation. It acts as a placeholder and does nothing when executed. It is used when syntactically a statement is required, but no action to be performed.
In the above code example, a class is created, and pass statement is used inside the class definition to indicate that there are no attributes or methods defined within the class yet.
Instantiation : Instantiation is the process of creating an instances of a class, known as object. Refer the code example below where my_car is an instance of the class Car.
Creation of Object : An object can be thought of as things or items in the real world. For example, a car, a truck, or a rocket. Each of these objects to be created we will have to follow a blueprint(class). Objects will have characteristics like color, size, speed, payload, make, etc., and perform actions like accelerating, braking, launching.Objects encapsulates both attributes and methods into a single entity.
Attributes : Attributes are those characteristics or properities of an object. These are like the adjectives that describe the object. For a car, attributes might include color, make,model and size.Attributes are associated with instances created.
Before going ahead and initializing attributes and methods,take a look at Magic Methods, which help in understanding the initialization of attributes, accessing and manipulation.
Magic methods : also known as dunder methods(due to their double underscore naming convention), are special method in python that have reserved names and are invoked by the python intrepreter in specific situations. Constructors, or "__init__" methods, are one category of magic methods, but there are many others that serve different purposes. Magic methods provide a way to customize the behavior of classes and objects in Python. They allow classes to define how they should behave in response to operations like object instantiation,attribute access, comparison and arithmetic operations.
Common magic methods :
Now that you have an clearer view of
What is class?,
Creation of a class,
What is an object?,
Instantiation of an object,
What is method?,
What is an attribute?,
What is magic methods?
Let's go ahead encapsulate attribute and methods to the instance created.
In the above example, if you look carefully, "__init__" method serves as the constructor of the class. Meaning, it is automatically called when a new instance of the class is created.Inside "__init__", the instance variables(name, make, model, price) are initialized with the values passed as arguments.
Self naming convention : "self " refers to the newy created instance of the class. When an object is created from a class, python automatically passes this instance as the first argument to the "__init__" method. As we know, every method inside a class must have atleast one parameter, "__init__" method passes "self" as its first argument, in other words, python passes objects itself as a first parameter.
There are several other things can be done on attribute to manipulate the state of the object and customize their behavior. These includes providing type annotations for parameters and return values in method definitions.
Along to that, optionally, a default parameter value for parameters can also be provided.
Validations : To check whether certain conditions are met based on the provided input data, validation plays a vital role. These validations can be applied to various types of data, including string, numbers, lists, etc,. The "assert" keyword in python can be used to perform validations. The "assert" statement checks whether a given condition is True. If the condition evaluates to True, the program continues execution normally; else raises an "AssertionError". Assert allows you to customize the error message, and pass it as the second argument.
Class Attributes / Static Attributes : So far, the attributes encapsulated within an instance, there is one catch that seems important, they are class attributes. Class attributes are associated with class rather than instances of the class. Unlike instance attributes, which are unique to each instance of class, class attributes are shared among all instance of the class and the class itself. Though they are defined within the class definition but outside of any class methods. This means that class attributes can be accessed via the class itself or through instances of the class. Class attributes are typically initialized outside the "__init__" method, as they are shared among all instances and do not belong to any specific instance. However, they can also be initialized inside the constructor.
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There is an important catch here, when a class attribute is called, it first searches the attribute on the instance level. If the attribute does not exist on the instance level,then the search continues to search the attribute on the class level. Now that we have covered encapsulation of attributes to instances as well as what are class attributes, let's push this towards methods.
Methods : Methods are the actions that an object can perform. These are like the verbs that describe what a object is capable of doing or simply what it can do. For a car, methods might include accelerating, braking, accelerating, and turning. Remember every method inside a class must have atleast one parameter.
Static Method : Static methods are defined within a class using "@staticmethod" decorator or by simply defining a method within the class and not including 'self' as the first parameter. Static methods do not have access to instance attributes or methods. They operate independently of any particular instance of the class. Static methods are associated with the class rather than the instance of the class. They are called using class name, not an instance of the class. Common use for static method include utility functions or helper methods that perform operations related to the class but do not require instance-specific data.
Class Method : Class methods are defined within a class, using "@classmethod" decorator. They receive the class itself('cls') as the first parameter, allowing them to access class-level attributes and methods. A class method can access instance attributes as well but not directly. Class methods primarily intended to operate on class level data and perform operations related to the class itself.
Now that being familiar, lets go ahead into other concepts of OOPS.
Inheritance : Inheritance is like passing down traits from parents to children. In OOP, it allows one class to inherit the attributes and methods from another class. This promotes code reuse and helps to create relationships between different classes. Inheritance is a fundamental concept that allows a new class(subclass / derived class) to inherit properties(attributes) and behaviors(methods) from an existing class(superclass / baseclass). The subclass can then extend or modify the functionality of the superclass while also inheriting its attribute and methods.
Superclass : The existing class from which properties and behaviors are inherited is called "superclass" or "base class". The new class that inherits from the superclass is called subclass or derived class. Additionally, the subclass can add new attributes and methods in addition to those inherited from the superclass.
There are different types of Inheritance in OOPS.
Single Inheritance : In single inheritance, a subclass inherits attributes and methods from only one superclass.
Multiple Inheritance : refers to when a subclass can inherit properties and behaviors from more than one superclass. This means that a class can have multiple parent classes, and it can inherit attributes and methods from all of them.While it offers flexibility and code reuse, multiple inheritance can also introduce complexity and potential issues like a diamond problem.
Multilevel Inheritance : refers to when a subclass inherits properties and behaviors from another subclass, which in turn inherits from another sperclass. This creates a chain of inheritance, allowing for the propogation of attributes and methods through multiple levels of the inheritance hierarchy. In multilevel inheritance, a subclass serves as both a superclass and a subclass, forming an hierarchy structure.
Hierarchical & Hybrid Inheritance : Hierarchical inheritance is a type of inheritance where a single superclass is inherited by multiple subclasses. It creates a tree-like structure where each subclass inherits attributes and methods from the same superclass, forming a hierarchy. In hierarchical inheritance, a single superclass serves as the parent class, and multiple subclasses serve as its children. Each subclass inherits attributes and methods from the superclass, and additional features can be added to each subclass as needed. Hierarchical inheritance promotes code reuse by allowing multiple subclasses to share common functionality inherited from the superclass.
Hybrid inheritance is a combination of multiple inheritance types, including hierarchical and/or multple inheritance. It allows the creation of complex inheritance structures where subclasses inherit properties and behaviors from multiple superclasses. In hybrid inheritance, subclasses can inherit from multiple superclasses, forming a more intricate inheritance hierarchy. This involve a mix a single , multiple, multilevel, and hierarchical inheritance relationships within the same class hierarchy. Hybrid inheritance offers greater flexibility in class design by allowing subclasses to inherit and combine features from different sources.
Polymorphism : Polymorphism is like having different forms or shapes. In OOP, it allows objects of different classes to be treated as objects of a common superclass. This allows for flexibility and enables different objects to be used interchangeably.
Method Overloading : Method overloading allows multiple methods in class to have the same name but different parameters. The appropriate method to be executed is determined based on the number and types of arguments passed at compile line.
Method Overriding : Method overriding allows a subclass to provide a specific implementation of a method that is already defined in its superclass. The appropriate method to be executed is determined at runtime based on the actual type of the object being referenced.
Compile-Time Polymorphism : also known as early or static binding or method overloading. Compile-time polymorphism occurs when the method or operation to be executed is determined at compile time based on the types of the arguments provided and their number. In python compile-time polymorphism is achieved through function or method overloading, where multiple methods with the same name but different parameters are defined with a class.
Run-Time Polymorphism : also known as late / dynamic binding or method overriding. Run-time polymorphism occurs when the method or operation to be executed is determined at run-time based on the actual type of the object being referenced. In python , runtime polymorphism is achiever through method overriding, where a method in a subclass has the same name and signature as a method in its superclass, effectively replacing the superclass method implementation with its own.
In conclusion, OOP is a fundamental paradigm for building robust, scalable, and maintainable software systems. By understanding and applying OOP principle effectively, developers can create modular, reusable, and flexible codebases that are easier to understand, test and maintain.
Though this article, we've explored key concepts of OOP, including encapsulation, classes, objects, inheritance, polymorphism, I would strongly suggest to read, understand and follow best practices of OOP and embracing OOP principles, write a cleaner, more maintainable code that meets the demands of modern software development.
As technology continues to evolve, proficiency in OOP remains essential for software developers looking to advance their careers and build innovative solutions. By mastering OOP concepts and incorporating best practices into the workflow, developers can unlock new opportunities and stay head in today's competitive job market.