Python Coding challenge - Day 851| What is the output of the following Python Code?

 

Code Explanation:

1. Defining Class R

class R:

You begin by creating a class named R, which will have an initializer and a private attribute.

2. Constructor of Class R

    def __init__(self):

        self.__v = 10

__init__ runs automatically when an object of R (or its child class) is created.

self.__v is a private attribute because it starts with double underscore __.

Python performs name-mangling, converting __v into _R__v internally.

This means subclasses cannot directly access __v using the name __v.

3. Defining Class S that Inherits R

class S(R):

Class S is a child class of R.

It inherits the constructor of class R, so __v is still created inside objects of class S (but as _R__v).

4. Method show() Inside Class S

    def show(self):

        return hasattr(self, "__v")

The method checks: Does the object have an attribute named "__v"?

Because of name-mangling, the actual attribute name is _R__v, not __v.

So hasattr(self, "__v") will return False.

5. Creating an Object of S and Calling show()

print(S().show())

An object of S is created → this also runs R’s constructor → _R__v is created.

Now show() is called.

hasattr(self, "__v") checks for "__v" exactly.

Since "__v" does not exist (only _R__v does), the result is:

False

Final Output: False

500 Days Python Coding Challenges with Explanation