Python Coding challenge - Day 1275| What is the output of the following Python Code?

 

Code Explanation:

1. 🏗️ Define the Class

class A:

A class named A is created.

2. 🔧 Define __setattr__()

def __setattr__(self, name, value):

__setattr__() is a special method that Python calls whenever you assign a value to an object's attribute.

For example:

a.x = 5

automatically triggers:

a.__setattr__("x", 5)

3. ✖️ Double the Assigned Value

object.__setattr__(self, name, value * 2)

Instead of storing the original value, the code stores:

value × 2

object.__setattr__() is used to perform the actual attribute assignment.

This is important because directly writing:

self.name = value

inside __setattr__() would call __setattr__() again and cause infinite recursion.

4. 🆕 Create the Object

a = A()

An object a is created.

No custom attribute assignment happens here.

5. 📌 Assign x

a.x = 5

Python calls:

__setattr__("x", 5)

The method doubles 5:

5 × 2 = 10

So:

a.x = 10

6. 📌 Assign y

a.y = 3

Again, __setattr__() intercepts the assignment.

3 × 2 = 6

So:

a.y = 6

7. 🧮 Calculate the Final Result

print(a.x + a.y)

Now:

a.x = 10

a.y = 6

Therefore:

10 + 6 = 16

✅ Final Output

16

Book: 500 Days Python Coding Challenges with Explanation