What is the necessity of using shallow copying of objects?

Shallow copying of objects is used when you need to create a new object that is a copy of the original, but nested objects are not copied, only references to them are copied. This is useful when the object structure is large, and deep copying (copying all nested objects) is too resource-intensive or not required.

For example, if you have an object with several attributes and you want to change only the top level without affecting nested objects, shallow copying allows you to avoid redundant data copying.

In Python, shallow copying can be performed using the copy module:

import copy

original = [1, 2, [3, 4]]
shallow_copy = copy.copy(original)

shallow_copy[2].append(5)
print(original)      # Outputs: [1, 2, [3, 4, 5]]
print(shallow_copy)  # Outputs: [1, 2, [3, 4, 5]]

Here, it is evident that modifying the nested list in the copy also affects the original, since the nested object was not copied but only a reference to it was.