How to Create a Symmetric Array in Python

 Here's a Python program that says to write a Symmetric array transformation. A top interview question.

Symmetric Array Transformation

Problem:

Write a Python function that transforms a given array into a symmetric array by mirroring it around its center. For example:

• Input: [1, 2, 3]
• Output: [1, 2, 3, 2, 1]

Hints:

• Use slicing for the reverse part.
• Concatenate the original array with its mirrored part.

Example

def symmetric_array(arr):

    """

    Transforms the input array into a symmetric array by mirroring it around its center.

    Parameters:

    arr (list): The input array.

    Returns:

    list: The symmetric array.

    """

    # Mirror the array by concatenating the original with its reverse (excluding the last element to avoid duplication)

    return arr + arr[-2::-1]

# Example usage

input_array = [1, 2, 3]

symmetric_result = symmetric_array(input_array)

print("Input Array:", input_array)

print("Symmetric Array:", symmetric_result)

Output:

For the input [1, 2, 3], the output will be:

Input Array: [1, 2, 3]
Symmetric Array: [1, 2, 3, 2, 1]

Explanation

1. arr[-2::-1]:

   • This slices the array in reverse order starting from the second-to-last element to avoid duplicating the middle element.

2. Concatenation (+):

   • Combines the original array with its mirrored part to create symmetry.