Python Coding challenge - Day 920| What is the output of the following Python Code?

 

Code Explanation:

1. Importing the copy Module

import copy

We import Python’s built-in copy module.

It provides two important copy operations:

copy.copy() → shallow copy

copy.deepcopy() → deep copy

2. Defining the Class

class Data:

A class named Data is being created.

It will store a list as attribute.

3. Constructor Method (__init__)

    def __init__(self):

        self.lst = [1]

__init__ runs when an object is created.

It creates an instance attribute lst, assigned to a list [1].

Important point:

Lists are mutable objects, which means they can be changed after creation.

4. Creating the First Object

d1 = Data()

A Data object named d1 is created.

Inside d1, we now have:

d1.lst → [1]

5. Making a Shallow Copy

d2 = copy.copy(d1)

copy.copy(d1) creates a shallow copy of d1.

For a shallow copy:

The outer object is copied, but inner mutable objects are shared.

So:

d1 and d2 are two different objects

but both point to the same list in memory

Meaning:

d1.lst and d2.lst refer to the SAME list

6. Modifying the List via d1

d1.lst.append(2)

We append 2 into the list inside d1.

Because the list is shared, the same change affects d2.lst.

Now the shared list becomes:

[1, 2]

7. Printing from d2

print(d2.lst)

What does it print?

Since d2.lst points to the same modified list,

the output will be:

[1, 2]

Final Output

[1, 2]

700 Days Python Coding Challenges with Explanation