Python Coding challenge - Day 765| What is the output of the following Python Code?

 Code Explanation:

1. Importing the weakref module

import weakref

weakref provides tools for creating weak references to objects.

A weak reference does not increase the reference count of an object.

This allows Python’s garbage collector to delete the object when no strong references exist.

2. Defining a simple class

class A: pass

A class A is defined.

It’s an empty class (pass means no attributes or methods inside).

3. Creating an object

obj = A()

An instance of A is created and stored in the variable obj.

This is a strong reference (normal variable pointing to the object).

4. Creating a weak reference

r = weakref.ref(obj)

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

r does not prevent the object from being garbage-collected.

Calling r() will return the object as long as it still exists.

5. Checking weak reference vs strong reference

print(r() is obj)

r() calls the weak reference, retrieving the original object.

Since the object still exists, r() returns the same obj.

r() is obj evaluates to True.

Output here: True

6. Deleting the strong reference

del obj

The strong reference obj is deleted.

Now, no strong references point to the object.

Since only a weak reference remains, Python’s garbage collector frees the object’s memory.

7. Checking the weak reference again

print(r() is None)

After garbage collection, the object no longer exists.

r() now returns None.

So r() is None evaluates to True.

Output here: True

Final Output

True

True

500 Days Python Coding Challenges with Explanation