Python extension methods

Question

OK, in C# we have something like:

public static string Destroy(this string s) { 
    return \"\";
}

So basically, when you have a string you ca

Answer 1

I would use the Adapter pattern here. So, let's say we have a Person class and in one specific place we would like to add some health-related methods.

from dataclasses import dataclass


@dataclass
class Person:
    name: str
    height: float  # in meters
    mass: float  # in kg


class PersonMedicalAdapter:
    person: Person

    def __init__(self, person: Person):
        self.person = person

    def __getattr__(self, item):
        return getattr(self.person, item)

    def get_body_mass_index(self) -> float:
        return self.person.mass / self.person.height ** 2


if __name__ == '__main__':
    person = Person('John', height=1.7, mass=76)
    person_adapter = PersonMedicalAdapter(person)

    print(person_adapter.name)  # Call to Person object field
    print(person_adapter.get_body_mass_index())  # Call to wrapper object method

I consider it to be an easy-to-read, yet flexible and pythonic solution.