Python Numpy matrix.diagonal() Function

Python / By

NumPy Library 

NumPy is a library in python that is created to work efficiently with arrays in python. It is fast, easy to learn, and provides efficient storage. It also provides a better way of handling data for the process. We can create an n-dimensional array in NumPy. To use NumPy simply have to import it into our program and then we can easily use the functionality of NumPy in our program.

NumPy is a Python library that is frequently used for scientific and statistical analysis. NumPy arrays are grids of the same datatype’s values.

Numpy matrix.diagonal() Function:

We can find a diagonal element from a given matrix using the Numpy matrix.diagonal() method, which returns a one-dimensional matrix as output.

Syntax:

 matrix.diagonal()

Return Value:

The diagonal element of a given matrix is returned by the diagonal() function.

Numpy matrix.diagonal() Function in Python

For 2-Dimensional (2D) Matrix

Approach:

  • Import numpy module using the import keyword
  • Create a matrix(2-Dimensional) using the matrix() function of numpy module by passing some random 2D matrix as an argument to it and store it in a variable.
  • Apply diagonal() function on the given matrix to get all the diagonal elements of a given matrix.
  • Store it in another variable
  • Print all the diagonal elements of a given matrix.
  • The Exit of the Program.

Below is the implementation:

# Import numpy module using the import keyword
import numpy as np
            
# Create a matrix(2-Dimensional) using the matrix() function of numpy module by passing 
# some random 2D matrix as an argument to it and store it in a variable
gvn_matrx = np.matrix('[2, 1; 6, 3]')
            
# Apply diagonal() function on the given matrix to get all the diagonal elements of a given matrix.
# Store it in another variable
rslt = gvn_matrx.diagonal()
# Print all the diagonal elements of a given matrix.
print("The diagonal elements of a given matrix:")
print(rslt)

Output:

The diagonal elements of a given matrix:
[[2 3]]

For 3-Dimensional (3D) Matrix

Approach:

  • Import numpy module using the import keyword
  • Create a matrix(3-Dimensional) using the matrix() function of numpy module by passing some random 3D matrix as an argument to it and store it in a variable.
  • Apply diagonal() function on the given matrix to get all the diagonal elements of a given matrix.
  • Store it in another variable
  • Print all the diagonal elements of a given matrix.
  • The Exit of the Program.

Below is the implementation:

# Import numpy module using the import keyword
import numpy as np
            
# Create a matrix(3-Dimensional) using the matrix() function of numpy module by passing 
# some random 3D matrix as an argument to it and store it in a variable
gvn_matrx = np.matrix('[2, 4, 1; 8, 7, 3; 10, 9, 5]')
            
# Apply diagonal() function on the given matrix to get all the diagonal elements of a given matrix.
# Store it in another variable
rslt = gvn_matrx.diagonal()
# Print all the diagonal elements of a given matrix.
print("The diagonal elements of a given matrix:")
print(rslt)

Output:

The diagonal elements of a given matrix:
[[2 7 5]]