Question

How to find the sum of each row and each column of a matrix (2D array) in Python

Answer 1

arr = [    
        [1, 2, 3, 5],  
        [4, 5, 6, 5],  
        [7, 8, 9, 5]  
    ];  
     
rows = len(arr);  
cols = len(arr[0]);  

for i in range(0, rows):  
    sumRow = 0;  
    for j in range(0, cols):  
        sumRow = sumRow + arr[i][j];  
    print("Sum of row:", i, "=", sumRow);  
     
for i in range(0, cols):  
    sumCol = 0;  
    for j in range(0, rows):  
        sumCol = sumCol + arr[j][i];  
    print("Sum of col:", i, "=", sumCol);  
      
      
      
      
'''
run:
  
Sum of row: 0 = 11
Sum of row: 1 = 20
Sum of row: 2 = 29
Sum of col: 0 = 12
Sum of col: 1 = 15
Sum of col: 2 = 18
Sum of col: 3 = 15

'''

 

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