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c#pythonoop
Alex Green
Alex Green

Reputation: 305

class vs static methods

I'm new in Python (come from C#), trying to figure out how OOP works here. Started from very begining I try to implement Vector class. I want to have basis vectors (i, j, k) defined in Vectorclass. In C#, I can do this like that:

public class Vector
{
    // fields...
    public Vector(int[] array){
        //...
    }

    public static Vector i(){
        return new Vector(new int[1, 0, 0]);
    }
}

Exploring Python I found 2 ways how to implement this: using either @classmethod or @staticmethod:

class Vector:
    def __init__(array):
        #...

    @classmethod
    def i(self):
        return Vector([1, 0, 0])

Since I don't need to have access to any information inside the class, should I really use @classmethod?

Upvotes: 0

Views: 112

Answers (1)

Izaak van Dongen
Izaak van Dongen

Reputation: 2545

I think you've confused yourself with your naming of arguments a bit. The first argument a class method receives is the class itself, which would be Vector, for now, until you have a subclass. A class method would be implemented like this:

    @classmethod
    def i(cls):
        return cls([1, 0, 0])

Generally, an instance method (no decorator) calls its first argument self, which is the instance. A class method has cls, which is the class, which can be used to construct an instance. A static method takes no "extra" argument, so your other option, if you want to always return a Vector, is:

    @staticmethod
    def i():
        return Vector([1, 0, 0])

Upvotes: 1

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