Classes and Objects in Python

In Python, everything is built around objects. Classes and objects let you combine data and behavior in one structure, making your programs easier to organize and reuse.

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📝 If You Want to Practice the Code

If you plan to practice the Python code mentioned within this blog post, you’ll need a working Python environment. You can execute the commands in one of the following ways (choose only one option):

• From a Python prompt in your terminal or command line – see Getting Started with Python and Virtual Environment in Python and How to Set One Up
• Using Miniconda and Jupyter Notebook – see How to Install and Set Up Miniconda and Install Jupytor Notebook Windows, How to Install and Set Up Miniconda on MacOS, How to Install and Set Up Miniconda on Linux (Ubuntu), and Getting Started with Jupyter Notebooks.
• On Google Colab (browser-based, no installation required) – see Getting Started with Google Colab.
• Through VS Code – see Setting Up VS Code for Python Development.

👉 Choose whichever environment you’re most comfortable with. If you haven’t set up Python yet, start with one of the installation posts before trying the examples here.

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Understanding Classes and Objects

• A class is like a blueprint.
• An object is a specific item created from that blueprint.

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🔹 Creating a Class

A class is defined using the class keyword.

class Student:
    pass

Here, Student is an empty class.

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🔹 Making an Object

Objects are created by calling the class:

s1 = Student()
print(type(s1))

👉 Output: <class '__main__.Student'>

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🔹 Adding Attributes

Classes can store data using attributes. Attributes are usually set in a special method called __init__.

class Student:
    def __init__(self, name, age):
        self.name = name
        self.age = age

s1 = Student("Alice", 20)
s2 = Student("Bob", 22)

print(s1.name, s1.age)   # Alice 20
print(s2.name, s2.age)   # Bob 22

• __init__ is the constructor: it runs when the object is created.
• self refers to the current object.

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🔹 Adding Methods

A class can also contain methods — functions that belong to the class.

class Student:
    def __init__(self, name, grade):
        self.name = name
        self.grade = grade

    def greet(self):
        print("Hello, my name is", self.name)

    def show_grade(self):
        print(self.name, "scored grade", self.grade)

s1 = Student("Alice", "A")
s1.greet()        # Hello, my name is Alice
s1.show_grade()   # Alice scored grade A

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🔹 Multiple Objects

Each object keeps its own copy of attributes:

s2 = Student("Bob", "B")
s2.greet()        # Hello, my name is Bob
s2.show_grade()   # Bob scored grade B

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📝 Mini Task

1. Create a class Car with attributes brand and year.
2. Add a method drive() that prints: "Brand is driving".
3. Create two car objects and call the method.

class Car:
    def __init__(self, brand, year):
        self.brand = brand
        self.year = year

    def drive(self):
        print(self.brand, "is driving")

c1 = Car("Toyota", 2020)
c2 = Car("Tesla", 2022)

c1.drive()   # Toyota is driving
c2.drive()   # Tesla is driving

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✅ Summary

• Class → A blueprint for creating objects.
• Object → An instance of a class.
• __init__ → Constructor that sets up attributes.
• self → Refers to the object itself.
• Methods → Functions inside a class that use or modify its data.

With classes and objects, you can build more structured and reusable programs.