Python Coding challenge - Day 352| What is the output of the following Python Code?

 

Code Explanation:

1. Importing the deque class

from collections import deque

We import deque from the collections module.

Think of a deque like a special list, but it is optimized for fast addition and removal of elements at both the beginning and the end.

2. Creating a deque

d = deque([1, 2, 3])

Here, we create a deque named d and initialize it with the list [1, 2, 3].

At this point, the deque contains these elements: 1, 2, 3.

Imagine the deque as a row of blocks where you can easily add or remove items from either side:

[1, 2, 3]

3. Adding an element to the front

d.appendleft(0)

The appendleft() method is used to add the element 0 to the left side of the deque.

After this operation, the deque becomes:

[0, 1, 2, 3]

This is different from a regular list where inserting an element at the beginning (list.insert(0, value)) is slower because it shifts all other elements. With deque, it’s fast and efficient.

4. Printing the deque

print(d)

This prints the entire deque, showing its contents in the following format:

deque([0, 1, 2, 3])

Visualizing the Operations

[1, 2, 3]

Use appendleft(0):

[0, 1, 2, 3]

Final Output

When you run the code, the output will be:

deque([0, 1, 2, 3])