What is the __call__ Method

The __call__ method is a special method in Python that allows instances of a class to be called as if they were functions. When a class implements the __call__ method, its instances become callable objects, which means you can use them in the same way you would use a function, with parentheses and arguments. This powerful feature enables you to create more expressive and flexible code by leveraging the full power of object-oriented programming in Python.

Syntax and Structure

To implement the __call__ method in your Python class, simply define a method named __call__ within the class. This method should take self as its first argument, followed by any additional arguments you want the callable instance to accept.

Here's the general syntax for the __call__ method:

class MyClass:
    def __call__(self, arg1, arg2, ..., argN):
        # Your implementation here

Basic Example of __call__ Method

Here's a basic example of the __call__ method in action:

class CallableGreeter:
    def __init__(self, greeting):
        self.greeting = greeting

    def __call__(self, name):
        return f"{self.greeting}, {name}!"

greeter = CallableGreeter("Hello")
print(greeter("Alice"))  # Output: Hello, Alice!

In this example, we define a class CallableGreeter with a __call__ method. When we create an instance of the class and provide a greeting, the instance becomes a callable object that can take a name as an argument and return a personalized greeting.

References

https://medium.com/@johnidouglasmarangon/using-call-method-to-invoke-class-instance-as-a-function-f61396145567