What is a Class?

In Python, everything is an object. But where do these objects come from? They come from Classes.

Think of a class as a blueprint or a template. If you want to build a house, the blueprint isn't the house itself—it just describes what the house will look like (how many rooms, windows, etc.). You can use that one blueprint to build as many actual houses (objects) as you want.

Another classic analogy is a cookie cutter. The class is the cutter. It defines the shape. The objects are the actual cookies you stamp out using that cutter.

Here is the simplest possible class in Python:

class Dog:
    pass

We've defined a blueprint called Dog. Right now, it doesn't do anything (that's what pass means), but it's a valid class.

Now, let's create an "instance" (an object) from this class:

my_dog = Dog()

my_dog is now a unique object created from the Dog blueprint. We can verify this:

print(my_dog)
# Output: <__main__.Dog object at 0x104...>

Classes become useful when we give them attributes (data) and methods (functions). For example, a Dog class might have a breed attribute and a bark() method. This allows you to bundle data and behavior together, making your code easier to organize and understand.

I explain class fundamentals and how to build complex systems with them in my Python OOP course.