Python class method

Let’s say, we want to use a function or method from a class without initializing the class. How can we do that?

Python @classmethod decorator here to help.

Let’s start with an example.

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    
    @classmethod
    def print_something(cls, input):
        print(input)

Person.print_something('hello')

Here if we want to use inside function of Person we have to initialize it, right? But using the @classmethod decorator we can call print_something method without initializing the Person class. Here cls means the class itself.

Let’s see another use cases.

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    
    @classmethod
    def from_dict(cls, input_dict):
        return cls(**input_dict)

input_dict = {'name': 'Sagor', 'age': 28}
person = Person.from_dict(input_dict)

We are creating a person instance from the classes and dynamically setting the hyper-parameters from input dict using the class method itself.