What methods of object copying do you know?

Shallow and deep copying.

Shallow Copy creates a new object, but references to nested objects remain the same. Changes in nested objects of the original object will reflect in the copy, and vice versa.

Deep Copy creates a completely independent copy of the object, including copying all nested objects. Changes in nested objects of the original do not affect the copy.

Examples of implementation (Python):

# Shallow copy
import copy

original_list = [1, 2, [3, 4]]
shallow_copy_list = copy.copy(original_list)

# Changing a nested object in the original affects the copy
original_list[2][0] = 99
# shallow_copy_list now [1, 2, [99, 4]]

# Deep copy
import copy

original_list = [1, 2, [3, 4]]
deep_copy_list = copy.deepcopy(original_list)

# Changing a nested object in the original does not affect the copy
original_list[2][0] = 99
# deep_copy_list remains [1, 2, [3, 4]]

The choice of method depends on the structure of the object and the task. For simple objects without nested references, shallow copying is sufficient. For objects with complex nesting or when full independence of the copy from the original is required, deep copying is used.