Python Coding challenge - Day 1031| What is the output of the following Python Code?

 

Code Explanation:

1. Defining the Metaclass

class Meta(type):

type is the default metaclass in Python.

By inheriting from type, Meta becomes a custom metaclass.

A metaclass controls how classes themselves are created.

📌 Normal class → creates objects

📌 Metaclass → creates classes

🔹 2. Overriding __new__ in the Metaclass

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

This method is called when a class is being created, not when an object is created.

Parameters:

cls → the metaclass (Meta)

name → class name being created ("Test")

bases → parent classes (())

dct → class namespace dictionary ({} initially)

🔹 3. Injecting a Method into the Class

dct["greet"] = lambda self: "Hello"

A new method named greet is dynamically added to the class.

lambda self: "Hello" acts like:

def greet(self):

    return "Hello"

This method becomes part of every class created using Meta.

🔹 4. Creating the Class Object

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

Calls type.__new__() to actually create the class

Uses the modified dictionary (now containing greet)

Returns the new class object → Test

📌 At this point, Test already has a greet() method.

🔹 5. Defining the Class Using the Metaclass

class Test(metaclass=Meta):

    pass

Python sees metaclass=Meta

Instead of using type, it uses Meta

This triggers:

Meta.__new__(Meta, "Test", (), {})

➡️ greet() gets injected into Test

🔹 6. Creating an Object of the Class

Test()

A normal object is created

No __init__ method exists, so nothing special happens

The object inherits greet() from the class

🔹 7. Calling the Injected Method

print(Test().greet())

Step-by-step:

Test() → creates an instance

.greet() → found in the class (added by metaclass)

self → instance of Test

Returns "Hello"

✅ Final Output

Hello

400 Days Python Coding Challenges with Explanation