python matrix addition code example

Example 1: addition of matrices in python

# Program to add two matrices using nested loop

X = [[12,7,3],
    [4 ,5,6],
    [7 ,8,9]]

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

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

# iterate through rows
for i in range(len(X)):
   # iterate through columns
   for j in range(len(X[0])):
       result[i][j] = X[i][j] + Y[i][j]

for r in result:
   print(r)

Example 2: how to add two matrices in python

matrix1 = [[0, 1, 2], [3, 4, 5], [6, 7, 8]]
matrix2 = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]


def addTheMatrix(matrix1, matrix2):
    matrix1Rows = len(matrix1)
    matrix2Rows = len(matrix2)
    matrix1Col = len(matrix1[0])
    matrix2Col = len(matrix2[0])

    #base case
    if(matrix1Rows != matrix2Rows or matrix1Col != matrix2Col):
        return "ERROR: dimensions of the two arrays must be the same"

    #make a matrix of the same size as matrix 1 and matrix 2
    matrix = []
    rows = []

    for i in range(0, matrix1Rows):
        for j in range(0, matrix2Col):
            rows.append(0)
        matrix.append(rows.copy())
        rows = []

    #loop through the two matricies and the summation should be placed in the
    #matrix
    for i in range(0, matrix1Rows):
        for j in range(0, matrix2Col):
            matrix[i][j] = matrix1[i][j] + matrix2[i][j]
            
    return matrix



print(addTheMatrix(matrix1, matrix2)) 
#output = [[1, 3, 5], [7, 9, 11], [13, 15, 17]]

Example 3: addition of matrices in python

# Program to add two matrices using list comprehension

X = [[12,7,3],
    [4 ,5,6],
    [7 ,8,9]]

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

result = [[X[i][j] + Y[i][j]  for j in range(len(X[0]))] for i in range(len(X))]

for r in result:
   print(r)