Intro to Python - Day 5 - Encapsulation in OOP

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Today I continue my boot.dev journey learning Object-Oriented Programming with Python. The topic of the day today is encapsulation.

In any programming language when you create a class or object, there may be variables or methods on the object that you don't want public.

Now encapsulation is not encryption. It's not enough of a safeguard to store truly sensitive information with on the class or object, but in Python it is a convention that helps other developers know which variables they should expose to the public and which should only be accessed with getter / setter methods, or internally within the class.

The convention in Python to designate a private variable is to use a double underscore. If we want to make a private ID method on our Student class, for example:

class Student:
    def __init__(self, name):
        self.name = name
        self.__id = 12345

This lets other developers know that the instance variable __id should not be exposed to the public, and developers should be careful manipulating this variable's value when using the class.

This convention in the language also uses what's called name mangling such that Python (mostly) disallows users from directly accessing variables on a class that start with a double-underscore.

Ideally, private variables are not accessed directly but if need be they should be exposed to the public via a getter method like so:

class Student:
    def __init__(self, name):
        self.name = name
        self.__id = 12345

    def get_student_id(self):
        return self.__id

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