In this Python tutorial, we will Classes and Objects in Pythom in a very simple way with examples that even a novice programmer will find easy to understand the concept of classes and objects.
Table of Contents
What Are Classes and Objects?
1. Classes
A class is a template or blueprint used to create objects. Just like a cookie cutter gives cookies their fun shapes, a class helps define the unique attributes and behaviours of the objects created from it.
Steps to create a class
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- Define it using the class keyword.
- It can contain attributes (variables) and methods (functions).
In the above example, Dog is a class. species is a class attribute, while name and age are instance attributes.
2. Objects
An object is a clear example that is instantiated from a class. For example, dog1 = Dog (“Buddy”, 3) creates a unique dog and sets its name and age.
Magic Method in Python
1. The __init__() Method
It is a function inside a class that is called whenever we create an object. It acts as a constructor. If you have noticed in the above example, we used the keyword self, which basically refers to the instance itself (e.g., dog1, dog2), as each instance will have its own attributes and methods.
2. The __str__ () Method
The __str__ method in Python gives us the wonderful ability to create our very own string representation for our objects, making them even more meaningful! By default, when we print an object or convert it to a string using str(), Python uses the default implementation, which returns a string like <__main__.ClassName object at 0x…>
Key Concepts of Classes
1. Class Variables vs. Instance Variables
- Class variables (like species), e.g., are accessible by all objects.
- Instance variables (name, age), e.g., are unique to each object.
2. Inheritance
It is one of the pillars of the object-oriented programming paradigm. It allows us to reuse the code from one class to another by inheriting the data members of the parent class. Let’s use the same example that we have implemented above. There are different types of inheritance (single, multilevel, multiple, hierarchical, and hybrid). Let’s see the implementation of single inheritance.
Here, you can notice that I am inheriting the class Dog in Labrador since Labrador is a child class of Dog. All the properties of the parent class will be accessible in the child class.
Advantages of Using Classes in Python
- Classes provide an easy way of keeping the data members and methods together in one place, which helps keep the program more organized.
- Using classes also provides another functionality of this object-oriented programming paradigm, that is, inheritance.
- Classes also help in overriding any standard operator.
- Using classes provides the ability to reuse the code, which makes the program more efficient.
- Grouping related functions and keeping them in one place (inside a class) provides a clear structure to the code, which increases the readability of the program.
Use Cases of Classes in 2025
- AI & Machine Learning: We use multiple libraries like TensorFlow and PyTorch to build machine learning models. They use the OOP approach only to create their modules.
- Web Development: Frameworks like Django use the concept of classes that allow the management of databases and user interactions.
- Automation: With the help of classes, we can simplify the scripting tasks like file management, API calls, etc.
Common Mistakes to Avoid
Common errors that we make as beginners while working with Python often involve mistakes with classes. It would significantly improve your coding abilities if you understood and corrected them.
1. Forgetting self in method definitions
In a class, every method has to possess self as a parameter (the first one as well). The self keyword is a reference for the current instance of a class. In simpler terms, it helps in accessing the attributes and methods of the object in a class. Not including ‘self’ will lead to an error.
2. Confusing class and instance variables
All instances of a class share the same class variables. Instance variables are unique to every object. The variable instance is often mistakenly defined as a class variable. Doing so results in unforeseen outcomes.
3. Overcomplicating inheritance hierarchies
By definition, inheritance lets you create new classes from existing ones. However, when too many layers of inheritance exist, it can lead to complex code maintenance. If the class hierarchy is too complicated, consider shifting from deep inheritance to composition. This means using attributes of other classes instead of creating multiple classes.
These problems can be skipped so that your Python programming techniques can be clean, optimized, and devoid of faults.
Conclusion
With developments in automation, AI, and IoT, these branches of technology are being implemented deeply with the help of Python’s OOP principles. By learning the Class Name of an Instance in Python, you will be able to write scalable and organized code. Start with a single class, play with inheritance, and become more skilled in Python!
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