Python Coding challenge - Day 1044| What is the output of the following Python Code?

 

Code Explanation:

🔹 1. Defining the Descriptor Class

class D:

Creates a class D

This class will act as a descriptor

🔹 2. Implementing __get__

def __get__(self, obj, objtype):

    return 99

__get__ makes D a descriptor

It controls how an attribute is read

Always returns 99

Parameters:

self → descriptor object

obj → instance accessing the attribute (a)

objtype → owner class (A)

📌 Important:

This descriptor defines only __get__, so it is a non-data descriptor.

🔹 3. Defining Class A

class A:

Creates a normal class A

🔹 4. Assigning Descriptor to Class Attribute

x = D()

x is a class attribute

Value is an instance of D

Since D has __get__, x is managed by the descriptor

🔹 5. Creating an Instance of A

a = A()

Creates object a

At this moment:

a.__dict__ is empty

x exists only in the class

🔹 6. Assigning to a.x

a.x = 5

What happens internally:

Python does NOT call the descriptor

Because D has no __set__

Python creates an instance attribute

a.__dict__['x'] = 5

📌 This overrides the descriptor for this instance.

🔹 7. Accessing a.x

print(a.x)

Attribute lookup order:

Instance dictionary (a.__dict__) → ✅ finds x = 5

Descriptor is skipped

Returned value is 5

✅ Final Output

5

500 Days Python Coding Challenges with Explanation