Python Coding challenge - Day 946| What is the output of the following Python Code?

 

Code Explanation:

1. Defining the Descriptor Class

class D:

A class named D is defined.

This class is a descriptor because it implements __get__.

2. Implementing the __get__ Method

    def __get__(self, obj, owner):

        return obj.__dict__.get("x", 0)

__get__ is called whenever the attribute x is accessed.

obj → the instance (a or b)

owner → the class (A)

It looks inside the instance dictionary (obj.__dict__) for "x".

If "x" exists, it returns its value; otherwise it returns 0.

So the descriptor stores values inside each object, not in the descriptor itself.

3. Using the Descriptor in a Class

class A:

    x = D()

x is a class attribute managed by descriptor D.

Any access to obj.x triggers D.__get__.

4. Creating Objects

a = A()

b = A()

Two separate instances of A are created: a and b.

Initially:

a.__dict__ = {}

b.__dict__ = {}

5. Assigning to a.x

a.x = 5

This does not call __set__ because D does not define __set__.

So Python treats a.x = 5 as a normal instance attribute assignment.

It creates:

a.__dict__["x"] = 5

6. Accessing b.x

print(b.x)

What happens internally:

Python finds x on the class as a descriptor.

Calls:

D.__get__(D_instance, b, A)

obj.__dict__ is b.__dict__, which is {}.

"x" is not found → returns 0.

7. Final Output

0

Final Answer

✔ Output:

0

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