concatenate two matrices python code example

Example 1: numpy merge arrays

>>> a = np.array([[1, 2], [3, 4]])
>>> b = np.array([[5, 6]])
>>> np.concatenate((a, b), axis=0)
array([[1, 2],
       [3, 4],
       [5, 6]])
>>> np.concatenate((a, b.T), axis=1)
array([[1, 2, 5],
       [3, 4, 6]])

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]]