Finding the sum of elements by column in a matrix October 19, 2018October 19, 2018 by mevan matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] # Assume a list is given for column in range(len(matrix[0])): total = 0 for row in range(len(matrix)): total += matrix[row][column] print("Sum for column", column, "is", total)