Python Coding challenge - Day 949| What is the output of the following Python Code?

 

Code Explanation:

1. Defining a Custom Metaclass

class Meta(type):

Meta is a metaclass because it inherits from type.

A metaclass controls how classes are created.

2. Overriding the Metaclass __new__ Method

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

        dct["x"] = dct.get("x", 0) + 1

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

This method runs every time a class using this metaclass is created.

Parameters:

cls → the metaclass (Meta)

name → class name ("A", "B")

bases → parent classes

dct → dictionary of class attributes

What it does:

Looks for key "x" in the class dictionary.

If "x" exists, it takes its value; otherwise uses 0.

Adds 1 to it and stores it back as "x".

So the metaclass increments x by 1 during class creation.

3. Creating Class A

class A(metaclass=Meta):

    x = 5

What happens internally:

Class body executes: dct = {"x": 5}

Meta.__new__(Meta, "A", (), {"x": 5}) is called.

Inside __new__:

dct["x"] = 5 + 1 = 6

Class A is created with:

A.x = 6

4. Creating Class B

class B(A):

    pass

B inherits from A, so it also uses metaclass Meta.

Class body is empty: dct = {}

Meta.__new__(Meta, "B", (A,), {}) is called.

Inside __new__:

dct["x"] = 0 + 1 = 1

So B gets its own class attribute:

B.x = 1

5. Printing the Values
print(A.x, B.x)

A.x is 6

B.x is 1

6. Final Output

6 1

900 Days Python Coding Challenges with Explanation