Python Coding challenge - Day 773| What is the output of the following Python Code?

 

Code Explanation:

Importing the deque class

from collections import deque

The deque (pronounced deck) is imported from Python’s built-in collections module.

It stands for double-ended queue, which allows fast appends and pops from both ends (left and right).

Much faster than normal lists when you modify both ends frequently.

Creating a deque with initial elements

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

A deque named dq is created containing [1, 2, 3].

Initially, the deque looks like this:

deque([1, 2, 3])

 Adding element to the left side

dq.appendleft(0)

The method .appendleft() inserts an element at the beginning of the deque.

Now the deque becomes:

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

Adding element to the right side

dq.append(4)

The .append() method adds an element to the right end (like normal list append).

Now the deque looks like:

deque([0, 1, 2, 3, 4])

Removing element from the right side

dq.pop()

.pop() removes the last (rightmost) element.

It removes 4.

The deque now becomes:

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

Removing element from the left side

dq.popleft()

.popleft() removes the first (leftmost) element.

It removes 0.

The deque now becomes:

deque([1, 2, 3])

Printing the final deque

print(list(dq))

Converts the deque into a list and prints it.

Output is:

[1, 2, 3]

Final Output

[1, 2, 3]

500 Days Python Coding Challenges with Explanation