Python Coding challenge - Day 1141| What is the output of the following Python Code?

 

Code Explanation:

🔹 1. Importing Module

import copy

✅ Explanation:

Imports Python’s built-in copy module.

This module provides:

copy.copy() → shallow copy

copy.deepcopy() → deep copy

🔹 2. Creating Nested List

a = [[1,2],[3,4]]

✅ Explanation:

a is a list of lists (nested structure).

Memory structure:

Outer list contains two inner lists

a → [ [1,2], [3,4] ]

🔹 3. Deep Copy

b = copy.deepcopy(a)

✅ Explanation:

Creates a completely independent copy of a.

Both:

Outer list

Inner lists

are copied separately.

🔍 Important:

b ≠ a

b[0] ≠ a[0]

✔️ No shared references

🔹 4. Modifying Copied List

b[0][0] = 100

✅ Explanation:

Changes first element of first inner list in b

So:

b → [ [100,2], [3,4] ]

🔹 5. Printing Original List

print(a)

✅ Explanation:

Since a and b are completely independent,

Changes in b do NOT affect a

🎯 Final Output

[[1, 2], [3, 4]]

Book:  700 Days Python Coding Challenges with Explanation