Question

How to sum 2D array (matrix) rows in JavaScript

Answer 1

function sum_matrix_rows(matrix, rows_sum)
{
    var rows = matrix.length;
    var cols = matrix[0].length;
    
    for (i = 0; i < rows; i++) {
        for (j = 0; j < cols; j++)
            rows_sum[i] += matrix[i][j]
    }
}

var matrix = [
  [11, 32, 13, 81],
  [20, 80, 50, 990]
];

var rows_sum = [0,0];

sum_matrix_rows(matrix, rows_sum);

for (var i = 0; i < 2; i++)
    document.writeln(rows_sum[i] + "<br />\n");

    
/*
run:
 
137
1140
  
*/

 

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