Shallow Copy vs Deep Copy: Key Differences

What is a Shallow Copy?

A shallow copy creates a new object, but inserts references to the objects found in the original. The copied object shares the same nested objects with the original object.

# Python example of shallow copy
import copy

original = [[1, 2, 3], [4, 5, 6]]
shallow = copy.copy(original)  # or original.copy() for lists
# Modifying nested object affects both
shallow[0][0] = 'X'
print(original)  # [['X', 2, 3], [4, 5, 6]] - original is affected!
print(shallow)   # [['X', 2, 3], [4, 5, 6]]

What is a Deep Copy?

A deep copy creates a new object and recursively copies all nested objects. The copied object is completely independent of the original.

# Python example of deep copy
import copy

original = [[1, 2, 3], [4, 5, 6]]
deep = copy.deepcopy(original)
# Modifying nested object only affects the copy
deep[0][0] = 'X'
print(original)  # [[1, 2, 3], [4, 5, 6]] - original unchanged!
print(deep)      # [['X', 2, 3], [4, 5, 6]]

Key Differences

1. Memory Allocation

Shallow Copy:

// JavaScript example
const…