Python Coding challenge - Day 1139| What is the output of the following Python Code?

 

Code Explanation:

🔹 1. Descriptor Class Definition

class Descriptor:

You define a class named Descriptor.

This will act as a descriptor because it implements special methods.

🔹 2. Defining __get__ Method

def __get__(self, obj, objtype):

    return 50

This makes the class a non-data descriptor (because only __get__ is defined).

Parameters:

self → descriptor instance

obj → instance of Test (i.e., obj)

objtype → class Test

Whenever the descriptor is accessed, it returns 50.

🔹 3. Test Class Definition

class Test:

A new class Test is defined.

🔹 4. Assigning Descriptor to Class Attribute

x = Descriptor()

x becomes a descriptor object.

It is stored in the class namespace (Test.__dict__).

This means x is controlled by descriptor behavior.

🔹 5. Object Creation

obj = Test()

Creates an instance of the Test class.

🔹 6. Setting Instance Attribute

obj.x = 100

This creates an instance attribute x inside obj.__dict__.

Important:

Since Descriptor is a non-data descriptor (no __set__),

instance attributes take priority over the descriptor.

🔹 7. Accessing obj.x

print(obj.x)

Let’s break the lookup process:

➤ Step-by-Step Attribute Lookup

Python checks:

Does class have a data descriptor (__get__ + __set__)?

❌ No → skip

Check instance dictionary:

obj.__dict__ → {'x': 100}

✔️ Found → returns 100

Descriptor is ignored because:

Non-data descriptors have lower priority than instance attributes

🔹 8. Final Output

100

Book: 100 Python Projects — From Beginner to Expert