Question

How to add two matrices in Python

Answer 1

matrix1 = [[1, 2, 3],
           [4, 5, 6],
           [7, 8, 9]]

matrix2 = [[1, 1, 1],
           [1, 1, 1],
           [1, 1, 1]]

result = [[0, 0, 0],
          [0, 0, 0],
          [0, 0, 0]]

for i in range(len(matrix1)):
    for j in range(len(matrix1[0])):
        result[i][j] = matrix1[i][j] + matrix2[i][j]

for row in result:
    for val in row:
        print('{:3}'.format(val), end="")
    print()
 


'''
run:
 
  2  3  4
  5  6  7
  8  9 10
 
'''

 

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Answer 2

matrix1 = [[1, 2, 3],
           [4, 5, 6],
           [7, 8, 9]]
 
matrix2 = [[1, 1, 1],
           [1, 1, 1],
           [1, 1, 1]]

result = [[matrix1[i][j] + matrix2[i][j] for j in range(len(matrix1[0]))] 
                                         for i in range(len(matrix1))]
 
for row in result:
    for val in row:
        print('{:3}'.format(val), end="")
    print()
  
  
  
'''
run:
  
  2  3  4
  5  6  7
  8  9 10
  
'''

 

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Answer 3

matrix1 = [[1, 2, 3],
           [4, 5, 6],
           [7, 8, 9]]
 
matrix2 = [[1, 1, 1],
           [1, 1, 1],
           [1, 1, 1]]

result = [map(sum, zip(*t)) for t in zip(matrix1, matrix2)]
 
for row in result:
    for val in row:
        print('{:3}'.format(val), end="")
    print()
  
  
  
'''
run:
  
  2  3  4
  5  6  7
  8  9 10
  
'''

 

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