Method parameter or instance attribute?

Question

Sometimes when I am designing a new method for a class that needs to act on certain variable, I can't say if it's better to pass this variable as a method parameter or if it's better to save this variable as an instance attribute and just use it inside the method. What are the advantages/disadvantages of both approaches?

class A:
    def __init__(self, data):
        self.data = data
    def my_method(self):
        # does something with self.data

Or

class B:
    def my_method(self, data):
        # does something with data

Andrew Jaffe · Accepted Answer · 2020-01-20 23:46:24Z

1

It depends on all the other things the class may do.

Most generally, what is the abstraction that your class encapsulates?

Does it need data for lots of operations, or only this? Will data change? If data is the "point" of this class, then it should probably be in the __init__, but if it uses data to act on the object, then probably not.

We need to know more....

answered Jan 20, 2020 at 23:46

Andrew Jaffe

27.2k4 gold badges54 silver badges59 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Method parameter or instance attribute?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related