How to create a matrix of random integers in Python ?

Prerequisites: numpy

To create a matrix of random integers in Python, randint() function of the numpy module is used. This function is used for random sampling i.e. all the numbers generated will be at random and cannot be predicted at hand.

Syntax :  numpy.random.randint(low, high=None, size=None, dtype=’l’)

Parameters :

• low : [int] Lowest (signed) integer to be drawn from the distribution.But, it works as a highest integer in the sample if high=None.
  
• high : [int, optional] Largest (signed) integer to be drawn from the distribution.
  
• size : [int or tuple of ints, optional] Output shape. If the given shape is, e.g., (m, n, k), then m * n * k samples are drawn. Default is None, in which case a single value is returned.
  
• dtype : [optional] Desired output data-type.

Return : Array of random integers in the interval [low, high) or a single such random int if size not provided.

Example 1:

Python3

# importing numpy library
import numpy as np

# random is a function, doing random sampling in numpy.
array = np.random.randint(10, size=(20))

# the array will be having 20 elements.
print(array)

Output:

 [2 6 1 4 3 3 6 5 0 3 6 8 9 1 6 4 0 5 4 1]

Example 2:

Python3

import numpy as np

# 1st argument --> numbers ranging from 0 to 9,
# 2nd argument, row = 2, col = 3
array = np.random.randint(10, size=(2, 3))
print(array)

Output:  

[[8 6 7]
 [2 9 9]]

Example 3:

Python3

import numpy as np


array = np.random.randint(2, size=(5, 5))
print(array)

Output:

[[0 0 1 0 0]

 [1 0 1 1 0]

 [0 1 0 1 0]

 [0 1 0 0 1]

[0 1 0 1 0]]