Python Coding challenge - Day 867| What is the output of the following Python Code?

 

Code Explanation:

1. Class P definition

class P:

Declares a new class named P.

P will act as a base (parent) class for other classes.

2. __init__ constructor in P

    def __init__(self):

        self.__v = 12

Defines the constructor that runs when a P (or subclass) instance is created.

self.__v = 12 creates an attribute named __v on the instance.

Because the name starts with two underscores, Python will name-mangle this attribute to _P__v internally to make it harder to access from outside the class (a form of limited privacy).

3. Class Q definition inheriting from P

class Q(P):

Declares class Q that inherits from P.

Q gets P’s behavior (including __init__) unless overridden.

4. check method in Q

    def check(self):

        return hasattr(self, "__v")

Defines a method check() on Q that tests whether the instance has an attribute literally named "__v" (not the mangled name).

hasattr(self, "__v") looks for an attribute with the exact name __v on the instance — it does not account for name mangling.

5. Create an instance of Q

q = Q()

Instantiates Q. Because Q inherits P, P.__init__ runs and sets the instance attribute — but under the mangled name _P__v, not __v.

6. Print the result of q.check()

print(q.check())

Calls check() which runs hasattr(self, "__v").

The instance does not have an attribute literally named __v (it has _P__v), so hasattr returns False.

The printed output is:

False

Final Output:

False

500 Days Python Coding Challenges with Explanation