What are strong and weak references in Python?

What are strong and weak references in Python?

In Python, a strong reference is the default type of reference that keeps an object in memory as long as the reference exists. A weak reference, on the other hand, allows the referenced object to be garbage collected if there are no strong references to it.

Can you give me an example of when to use weak references?

Sure! Weak references are useful in caching scenarios where you want to allow objects to be garbage collected when memory is needed, but still want to access them if they are available.

How do I create a weak reference in Python?

You can create a weak reference using the weakref module. For example:

import weakref

class MyClass:
    pass

obj = MyClass()
weak_ref = weakref.ref(obj)

This creates a weak reference to obj.

What happens if the object is garbage collected?

If the object is garbage collected, the weak reference will return None when accessed. This allows you to check if the object still exists without preventing its collection.