Question

What will be the output of the following Python code?
a = [1, 2, 3]
print(a[::-1])

• A. [1, 2, 3]
• B. [3, 2, 1]
• C. Error
• D. None

Hint:

The slice [::-1] is the "Pythonic" way to reverse a list or string. It’s concise, fast, and very common in coding interviews!

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
This question tests your knowledge of "Slicing" in Python. Slicing allows you to access a specific range or order of elements in a sequence like a list or string.

Step 2: Detailed Explanation:
The syntax for slicing is [start:stop:step].
• In the code a[::-1], the start and stop values are omitted, which means Python considers the whole list.
• The step value is -1. A negative step means the list is traversed backwards.
• Therefore, a[::-1] creates a new list starting from the last element and moving to the first.

Step 3: Final Answer:
The output will be the reversed list: [3, 2, 1].