How to implement copy and deepcopy functions in Python?

The implementation of copy and deepcopy is based on the copy module.

For copy: Creates a shallow copy of an object. For composite objects (lists, dictionaries, etc.), it creates a new container, but the elements inside are references to the original objects.

import copy

# Original list
original_list = [[1, 2], [3, 4]]

# Shallow copy
copied_list = copy.copy(original_list)

# Modifying an element in the nested list of the original
original_list[0][0] = 99

# copied_list[0][0] will also change, as both lists refer to the same nested list

For deepcopy: Creates a deep copy of an object. It creates new containers and recursively copies all elements inside composite objects.

import copy

# Original dictionary
original_dict = {'a': [1, 2], 'b': {'c': 3}}

# Deep copy
deep_copied_dict = copy.deepcopy(original_dict)

# Modifying an element in the nested list of the original
original_dict['a'][0] = 99

# deep_copied_dict['a'][0] will remain unchanged

Key differences:

Characteristic	copy.copy()	copy.deepcopy()
Nested objects	Performs a shallow copy, references original objects.	Performs a recursive copy.
Efficiency	Faster for large structures.	Slower for large structures.
Memory consumption	Less.	More.
Modification of original	May affect the copied object.	Does not affect the copied object.