_new_ in Python

The Python __new__ method is a special method that you can define in a class. It is responsible for creating a new instance of the class. While the __init__ method is used for initializing the attributes of an instance after it has been created, the __new__ method is responsible for the actual creation of the instance.

Here’s a basic example of how you can define and use the __new__ method in a Python class:

class MyClass:
    def __new__(cls, *args, **kwargs):
        print("Creating a new instance of MyClass")
        instance = super().__new__(cls)
        return instance

    def __init__(self, value):
        print("Initializing an instance of MyClass")
        self.value = value

# Creating an instance of MyClass
obj = MyClass(42)

In this example:

• The __new__ method is defined within the MyClass class. It takes the class itself (cls) as its first argument, followed by any additional arguments (*args) and keyword arguments (**kwargs). It returns a new instance of the class using super().__new__(cls).
• The __init__ method is also defined within the class. It initializes the value attribute of the instance.
• When an instance of MyClass is created (obj = MyClass(42)), Python first calls the __new__ method to create a new instance, and then it calls the __init__ method to initialize it.
• In this example, we’ve added print statements to show the order of execution. The __new__ method is called before __init__, and you can see the output indicating this order.

The use of the __new__ method is relatively rare in typical Python code because most object creation and initialization is handled by the __init__ method. However, there are advanced use cases where customizing __new__ can be beneficial, such as creating immutable objects or implementing singletons.