PYTHON

python diagonal sum

# A simple Python3 program to find
# sum of diagonals
MAX = 100
 
def printDiagonalSums(mat, n):
 
    principal = 0
    secondary = 0
    for i in range(0, n):
        principal += mat[i][i]
        secondary += mat[i][n - i - 1]
         
    print("Principal Diagonal:", principal)
    print("Secondary Diagonal:", secondary)
 
# Driver code
a = [[ 1, 2, 3, 4 ],
     [ 5, 6, 7, 8 ],
     [ 1, 2, 3, 4 ],
     [ 5, 6, 7, 8 ]]
printDiagonalSums(a, 4)
 
# This code is contributed
# by ihritik

matrix diagonal sum Python

# Problem Link : https://leetcode.com/problems/matrix-diagonal-sum/

class Solution(object):
    def diagonalSum(self, array):
        """
        :type array: List[List[int]]
        :rtype: int
        """
        n = len(array)
        primary = 0
        secondary = 0;
        for i in range(0, n):
            primary += array[i][i]
            secondary += array[i][n-i-1]
        if (n % 2 == 0): return primary + secondary
        else: return primary + secondary - array[n//2][n//2]

how to sum numpy matrix diagonal

np.trace(matrix)

Matrix Diagonal Sum

// Problem Link : https://leetcode.com/problems/matrix-diagonal-sum/

class Solution {
    public int diagonalSum(int[][] mat) {
        int n = mat.length;
        int principal = 0, secondary = 0;
        for (int i = 0; i < n; i++) {
            principal += mat[i][i];
            secondary += mat[i][n - i - 1];
        }
        return n%2 == 0 ? (principal + secondary) : (principal + secondary - mat[n/2][n/2]);
    }
}

sum of diagonal numpy

arr= np.arange(16)
arr= np.reshape(arr,(4,4))

a=np.diagonal(arr, 0,0,1)

result=sum(a)
print(result)