What is the need to define a function to return a class's attribute?

Question

I came across some code like this

class Student(Person):
    def __init__(self, age):
        self.age = age

    def get_age(self):
        return self.age

Could you please explain the purpose of the function get_age()? If we want to know a student’s age, can’t we simply do this:

student = Student(20)
student_age = student.age

Asked By: Nemo

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Source

Answer 1

Instead of a function like get_age, a property should be used. Both approaches have the advantage over a direct attribute access that later changes to the way how the requested data is retrieved by the object don’t require changes to the way the data is accessed from outside of the object.

Example:

Initial code:

class Student:
    def __init__(self, age):
        self._age = age

    @property
    def age(self):
        return self._age

print(Student(23).age)

Can be changed (just an example, don’t do date calculation like that) to:

from datetime import date

class Student:
    def __init__(self, age):
        self._birthyear = date.today().year - age

    @property
    def age(self):
        return date.today().year - self._birthyear

print(Student(23).age)

The last line accessing the age didn’t change.

Answered By: Michael Butscher

What is the need to define a function to return a class's attribute?

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