Python Coding challenge - Day 556| What is the output of the following Python Code?

 

Code Explanation:

1. Importing the weakref Module

import weakref

Brings in the weakref module which allows the creation of weak references — special references that don't prevent an object from being garbage collected.

2. Creating an Object and a Weak Reference

ref = weakref.ref(obj := type('MyClass', (), {})())

Breakdown:

type('MyClass', (), {}) dynamically creates a new class named 'MyClass' with no base classes and no attributes.

Appending () instantiates this class.

obj := ... (walrus operator) assigns the instance to obj.

weakref.ref(obj) creates a weak reference to the object.

The weak reference is stored in the variable ref.

At this point:

obj holds a strong reference to the instance.

ref() can still return the object.

3. Checking if the Weak Reference Matches the Original Object

print(ref() is obj)

Calls the weak reference ref() which returns the object (since it's still alive).

Compares it with obj using is (identity comparison).

Output: True

4. Deleting the Strong Reference

del obj

Deletes the strong reference obj.

Since no strong references remain, the object is now eligible for garbage collection.

Python may garbage collect the object immediately.

5. Checking if the Object was Garbage Collected

print(ref() is None)

Calls the weak reference again.

Since the object has been garbage collected, ref() returns None.

Output: True

Final Output

True

True

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