Python Coding challenge - Day 1019| What is the output of the following Python Code?

 

Code Explanation:

1. Creating an Empty List

names = []

A global list named names is created.

This list will be used to store class names.

2. Defining the Base Class

class Base:

A class named Base is defined.

It will act as a parent class for other classes.

3. Defining __init_subclass__

    def __init_subclass__(cls):

        names.append(cls.__name__)

__init_subclass__ is a special class method.

It is automatically called whenever a subclass of Base is created.

cls refers to the new subclass, not Base.

cls.__name__ gets the name of the subclass.

That name is appended to the names list.

4. Creating Subclass A

class A(Base): pass

What happens internally:

Python creates class A.

Since A inherits from Base, Python automatically calls:

Base.__init_subclass__(A)

"A" is added to names.

Now:

names == ["A"]

5. Creating Subclass B

class B(Base): pass

What happens:

Python creates class B.

Because B also inherits from Base, Python calls:

Base.__init_subclass__(B)

"B" is added to names.

Now:

names == ["A", "B"]

6. Printing the List

print(names)

Prints all collected subclass names.

7. Final Output

['A', 'B']

✅ Final Answer

✔ Output:

['A', 'B']

100 Python Programs for Beginner with explanation