Difference Between Shallow Copy and Deep Copy in Python.

In Python, when working with objects and data structures, it is important to understand the concepts of shallow copy and deep copy. These techniques allow us to create copies of objects or data structures while preserving their integrity and avoiding unexpected side effects.

Shallow copy in Python

A shallow copy creates a new list, but does not create copies of the objects that the original list references. Both the original and the cloned list will still reference the same objects.

Now let's try to make changes to the shallow list. You will see that the content of the original list doesn't get changed.

Now, let's try to make a shallow copy of a nested list. You will see that the changes made in the objects of items of shallow copied list also get reflected in the original list and vice versa.

For example, [1,2,3,4] is an item, with 1,2,3,4 as its objects.

However, when we try to append an item to a shallow copied list, it does not appear in the original list, and vice versa.

Deep copy in Python

A deep copy creates a new list and creates copies of every object in the original list references, recursively, ensuring that the two lists are entirely independent.

Python’s copy module provides the deepcopy() function to perform deep copies. Let’s see how it can be used:

Now let's make changes in the nested deep copy. You will see that the original list content changes will not reflect the deep copy list content, and vice versa.

Shallow copy and deep copy are valuable techniques in Python for creating copies of objects. While shallow copy shares reference to nested elements, deep copy creates independent copies. Understanding their differences is important for managing object integrity and avoiding unexpected side effects.