Python Coding challenge - Day 1135| What is the output of the following Python Code?

 

Code Explanation:

🔹 1. Class Definition

class Test:

✅ Explanation:

A class Test is created.

It overrides the special method __setattr__.

🔹 2. Overriding __setattr__

def __setattr__(self, name, value):

✅ Explanation:

__setattr__ is called every time you assign a value to an attribute.

Example:

obj.x = 5

internally becomes:

obj.__setattr__("x", 5)

🔹 3. Condition Check

if name == "x":

    value = value * 2

✅ Explanation:

If the attribute being assigned is "x":

Modify the value before storing it

Multiply it by 2

🔍 In this case:

value = 5 → 10

🔹 4. Calling Parent __setattr__

super().__setattr__(name, value)

✅ Explanation:

This is VERY IMPORTANT

It actually assigns the value to the object

⚠️ Why super() is needed:

If you write:

self.x = value

→ it would call __setattr__ again → infinite recursion

✔️ So we use:

super().__setattr__()

🔹 5. Object Creation

obj = Test()

✅ Explanation:

An object obj of class Test is created.

🔹 6. Assigning Value

obj.x = 5

🔍 What happens internally:

Calls:

__setattr__(obj, "x", 5)

Inside method:

Condition matches → value becomes:

10

Then:

super().__setattr__("x", 10)

✔️ So actual stored value is:

x = 10

🔹 7. Accessing Attribute

print(obj.x)

✅ Explanation:

Now x already stored as 10

So it prints:

10

🎯 Final Output

10

Book:  500 Days Python Coding Challenges with Explanation