__init__ python function with example in 2023

In this blog, we will learn everything about the __init__ python function. We will understand the init python function with several examples. So let’s get started.

what is __init__ python function?

In Python, the __init__ method is a special method that is automatically called when an object of a class is created. The __init__ method is a constructor method in Python classes and is defined using the double underscore syntax, which indicates that it is a special method.

Syntax of __init__ python function

The syntax of the __init__ python classes is as follows:

def __init__(self, [args]):
    [initialization code]

• The self argument is passed as the first argument to the __init__ method, it is a reference to the object being created.
• Additional arguments can be passed after the self argument, which can be used to set the initial values of the attributes of the object. These additional arguments can be any valid Python data types, such as strings, integers, lists, etc.
• The __init__ method does not return anything, it only initializes the object’s attributes.
• The __init__ method is defined within the class block and is indented under the class definition.

The def keyword is used to define a function, in this case, the __init__ method.__init__ method is also a good place to do some extra setup for an object, such as opening a file, creating a connection to a database, etc.

__init__ python example

Below is an example of how the __init__ method can be used in a Python class:

class Employee:
    def __init__(self, name, location):
        self.name = name
        self.location = location

employee1 = Employee("Tom", "USA")
employee2 = Employee("Jack", "India")

print(employee1.name)
print(employee1.location)
print(employee1.name)
print(employee2.location)

• The above code defines a class Employee with an __init__ method that takes two arguments, name and location, and sets the name and location attributes of the object to the values of the name and location arguments respectively.
• Two objects of the Employee class, employee1 and employee2, the __init__ method is automatically called and the name and location attributes of each object are set to the values passed as arguments while creating the objects.
• Finally, we are printing the name and location attributes of both objects.

Call a function in __init__ python

In Python, it is possible to call a function within the __init__ method of a class. You can call any function within the __init__ method by using its name followed by parentheses.

class Employee:
    def __init__(self, name, location, age):
        self.name = name
        self.location = location
        self.age = age
    def set_age(self, age):
        self.age = age

employee1 = Employee("Tom", "USA" ,30)
print(employee1.name)
print(employee1.location)
print(employee1.age)

• A class Employee with an __init__ method that takes three arguments, name, location, and age, and sets the name, location and age attributes of the object to the values of the name, location and age arguments respectively.
• A method set_age which takes one argument age and sets the age attribute of the object to the value of the age argument.
• An object of the Employee class, employee1, the __init__ method is automatically called and the name, location and age attributes of the object are set to the values passed as arguments while creating the object.
• Finally printing the name, location and age attributes of the object.

Python class without __init__

In Python, a class can be defined without an __init__ method. If a class does not have an __init__ method, the objects of the class will not have any initial state when they are created. Below is an example of a class without a __init__ method:

class MyEmployee:
    pass

employee1 = MyEmployee()

The MyEmployee class does not have an __init__ method. When we create an object of the MyEmployee class, the object does not have any initial state, and we can’t pass any arguments to it.

You can add attributes to the object after it’s created and also add methods to the class and use them on the created object.

employee1.name = "John"
print(employee1.name)

In this case, you can add attributes to the object after it is created and you can also add methods to the class and use them on the created object.

It’s also worth noting that, even if a class doesn’t define a __init__ method, it still inherits the __init__ method of its parent class, if it has one.

__init__ method with inheritance in python

In Python, the init method is used to initialize the attributes of the object. When a class inherits from another class, the child class can use the init method of the parent class by calling the super() function. This allows the child class to inherit the attributes and behavior of the parent class, while also adding its own unique attributes and behavior.

Let’s take the below example

class my_parent_class:
    def __init__(self, x):
        self.x = x

class my_child_class(my_parent_class):
    def __init__(self, x, y):
        super().__init__(x)
        self.y = y

c = my_child_class(1, 2)
print(c.x)
print(c.y)

This code defines a class my_parent_class with an init python method that initializes the x attribute. Then it defines a child’s class my_child_class that inherits from my_parent_class and has an __init__ method that initializes x and y attributes. It then creates an instance of my_child_class and assigns the values 1 to x and 2 to y. And then it prints the values of x and y.

Conclusion

I hope you have liked this tutorial on the init python function. Please do let me know if you are facing any issues while following along.

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