Understanding Python’s init Method: Object Initialization in Depth

4 min readOct 1, 2023

The __init__ method is a special function in Python that's used to initialize objects when they are created. It allows you to set up the initial state or attributes of an object.

Python __init__ is used to ensure that when you create an object from a class (like creating a toy or a car from a blueprint), it starts with the right characteristics or properties. It's like making sure your toy is the right color or your car has the correct make and model from the moment you create it.

The __init__ method is essential for setting up the initial conditions of objects in Python, ensuring they start with the right values.

Let’s explore Python init method in depth with following 5 examples:

Example 1: Simplest use of `init`

class Toy:
    def __init__(self):
        self.color = "red"

my_toy = Toy()
print(my_toy.color) # output = red

In this code block:

Imagine you have a magical toy (Python Class), and every magical toy has a color (Attribute). In this case, our toy is always red (Value of the attribute).
When we create a new magical toy (my_toy), it automatically becomes red because of the __init__ magic.
So, when we ask our toy what color it is, it says “red”, by default.
All toys are red in color here.

Example 2: `init` with a Parameter

class Toy:
    def __init__(self, color):
        self.color = color

my_toy = Toy("blue")
print(my_toy.color)

In this code block:

Now, our magical toy can be any color you like, not just red. When you create it, you can tell it what color you want.
Here, we make a new magical toy (my_toy) and say it should be "blue."
So, when we ask our toy what color it is, it says “blue.”

Example 3: init with Multiple Parameters

class Toy:
    def __init__(self, color, size):
        self.color = color
        self.size = size

my_toy = Toy("green", "small")
print(my_toy.color)
print(my_toy.size)

In this code block:

Our magical toy has two important things: color and size.
When we create a new magical toy (my_toy), we tell it both the color ("green") and size ("small").
So, when we ask our toy about these things, it tells us it’s “green” and “small.”

Example 4: init with Default Values

class Toy:
    def __init__(self, color="red", size="medium"):
        self.color = color
        self.size = size

my_toy1 = Toy()  # No specific color or size given
my_toy2 = Toy("blue")  # Only color is specified

print(my_toy1.color, my_toy1.size)
print(my_toy2.color, my_toy2.size)

In this code block:

Our magical toy can have default values for color (“red”) and size (“medium”).
When we create a new magical toy (my_toy1) without telling it anything, it becomes red and medium-sized because of the defaults.
When we create another magical toy (my_toy2) and only tell it the color ("blue"), it becomes blue but still medium-sized because we didn't say anything about the size.

Example 5: init with Complex Objects

class Car:
    def __init__(self, make, model, year, color="white"):
        self.make = make
        self.model = model
        self.year = year
        self.color = color

my_car = Car("Toyota", "Camry", 2023)
print(f"My car is a {my_car.year} {my_car.make} {my_car.model} in {my_car.color}.")

In this code block:

Now, we’re creating a magical car, not just a toy. Our car has many things, like the make (“Toyota”), model (“Camry”), year (2023), and color (default is “white”).
When we create our car (my_car), we tell it all these details.
So, when we ask our car about itself, it proudly says, “My car is a 2023 Toyota Camry in white.”

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