# Subtracting One Matirx From Another Using Numpy.ndarray With Example

## Overview:

• For subtracting one matrix from another matrix, the dimensions of both the matrices should be equal.

• Subtraction of two matrices is similar to adding two matrices.

• To subtract Matrix-B from Matrix-A, subtract each entry of Matrix-B from the corresponding entry of Matrix-A and place the result in the same position of the new matrix.

• numpy.ndarray has __sub__() method which subtracts one ndarray object from another and returns the resultant ndarray object.

## Example:

 # import numpy module import numpy as np   # import python standard library module - random import random   # Function to populate a matrix with random data def FillMatrix(matrix_in):     for x in range(0, matrix_in.shape[0]):         for y in range(0, matrix_in.shape[1]):             matrix_in[x][y] = random.randrange(2, 10) + 2   # Create two 4x4 matrices using ndarray matrix1 = np.ndarray((4,4)) matrix2 = np.ndarray((4,4))   # Fill the matrices i.e., the two dimensional arrays created using ndarray objects FillMatrix(matrix1) FillMatrix(matrix2)   # Add two matrices - two nd arrays add_results = matrix1.__sub__(matrix2)   # Print Matrix1 print("Matrix1:") print(matrix1)   # Print Matrix2 print("Matrix2:") print(matrix2)   # Print the results of subtracting two matrices print("Result of subtracting Matrix1 and Matrix2:") print(add_results)

## Output:

Matrix1:

[[  5.   9.   5.   8.]

[  4.  10.  11.   9.]

[  9.   5.   6.   5.]

[ 10.  10.  10.   8.]]

Matrix2:

[[  9.  10.   9.   4.]

[  9.   6.   8.   4.]

[  9.  11.  11.   4.]

[  6.   4.   8.  11.]]

Result of subtracting Matrix1 and Matrix2:

[[-4. -1. -4.  4.]

[-5.  4.  3.  5.]

[ 0. -6. -5.  1.]