# How to Solve the Diagonal Difference Challenge on HackerRank Using Python?

The Diagonal Difference Challenge on HackerRank asks you to find the absolute difference between the sums of the diagonals in a square matrix. Here is an example of how to solve this challenge in Python:

``````def diagonal_difference(arr):
# calculate the sums of the diagonals
diag1 = sum(arr[i][i] for i in range(len(arr)))
diag2 = sum(arr[i][len(arr)-i-1] for i in range(len(arr)))
# calculate the absolute difference between the sums
return abs(diag1 - diag2)

# test the function with a sample input
arr = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
print(diagonal_difference(arr))``````

In this solution, we define a function `diagonal_difference` that takes a square matrix `arr` as input. The function calculates the sum of the main diagonal (top-left to bottom-right) and the sum of the secondary diagonal (top-right to bottom-left) using list comprehension and the `sum` function.

The function then calculates the absolute difference between the sums of the diagonals using the `abs` function and returns the result.

In the main part of the script, we test the function with a sample input matrix `arr` and print out the result.

To use this function with HackerRank, simply copy and paste the `diagonal_difference` function into the HackerRank editor and call it with the input matrix provided in the challenge.