Python Coding challenge - Day 700| What is the output of the following Python Code?

 

Code Explanation:

1) class Meta(type):

Defines a metaclass called Meta.

Since it inherits from type, it means this class is used to control how other classes are created.

Normal classes create objects.

A metaclass creates classes themselves.

2) def __new__(cls, name, bases, dct):

__new__ is called when a new class (not object) is being created.

Parameters:

cls → the metaclass itself (Meta).

name → name of the class being defined (e.g., "A").

bases → tuple of base classes for inheritance.

dct → dictionary of attributes and methods defined in the class body.

3) dct['id'] = 100

Before the class is created, we inject a new class attribute id into its dictionary.

This means every class using this metaclass will automatically have id = 100.

4) return super().__new__(cls, name, bases, dct)

Calls the parent (type.__new__) to actually create the class with the modified dictionary.

Without this, the class A would not be created.

5) class A(metaclass=Meta):

Defines a new class A.

Instead of the default type metaclass, it uses our custom Meta.

When Python sees this, it calls Meta.__new__ to create A.

Inside Meta.__new__, id = 100 is added.

6) print(A.id)

Since the metaclass injected id = 100, class A has a class attribute id.

Prints:

100

Final Output

100

500 Days Python Coding Challenges with Explanation