Python random array

In Python, we have the random module used to generate random numbers of a given type using the PRNG algorithm. Here, we are going to discuss the list of available functions to generate a random array in Python.

Python random array using rand

The Numpy random rand function creates an array of random numbers from 0 to 1. Here, you have to specify the shape of an array.

import numpy as np
 
arr = np.random.rand(7)
 
print('-----Generated Random Array----')
print(arr)
 
arr2 = np.random.rand(10)
print('\n-----Using rand----')
print(arr2)

Generating random array using numpy rand function

-----Generated Random Array----
[0.72324285 0.902257 0.19086646 0.9848013 0.30726131 0.75984849
0.11788513]


-----Using rand----
[0.14238328 0.76333895 0.00358847 0.98198312 0.5848289 0.56392288
0.35347529 0.18018618 0.01869014 0.77321169]

Python numpy 2D Random Array

Here, we are using this random rand function to generate a two dimensional array.

import numpy as np
 
arr = np.random.rand(2, 2)
 
print('-----Generated Two Dimensional Array----')
print(arr)
 
arr2 = np.random.rand(4, 5)
print('\n-----Generated Two Dimensional Array----')
print(arr2)

2D random numpy Array

-----Generated Two Dimensional Array----
[[0.05429576 0.8120831 ]
[0.36443455 0.46820556]]

-----Generated Two Dimensional Array----
[[0.53800077 0.70044703 0.25007049 0.24959807 0.05361196]
[0.47492029 0.52460608 0.52157766 0.82260612 0.69135087]
[0.05602937 0.97118117 0.10938115 0.05648402 0.05137225]
[0.8724333 0.10477049 0.39284046 0.6794777 0.05015464]]

Numpy 3D Random Array

Let us create a three-dimensional array using the random rand function.

import numpy as np
 
arr = np.random.rand(2, 2, 2)
 
print('-----Generated Three Dimensional Random Array----')
print(arr)
 
arr2 = np.random.rand(2, 4, 5)
print('\n-----Generated Three Dimensional Random Array----')
print(arr2)

3D random Array output

-----Generated Three Dimensional Random Array----
[[[0.47091454 0.00534269]
  [0.31374026 0.72377206]]

 [[0.35134082 0.81840205]
  [0.43662241 0.74013157]]]

-----Generated Three Dimensional Random Array----
[[[0.1361512  0.7146421  0.19965805 0.9579547  0.53017549]
  [0.85335786 0.78601753 0.92519525 0.28573707 0.82727768]
  [0.13179852 0.31101528 0.39261411 0.96552699 0.41586368]
  [0.00234082 0.94735564 0.04102073 0.79654052 0.21729369]]

 [[0.45856543 0.34984498 0.49087227 0.18287609 0.99288025]
  [0.27352962 0.81479204 0.53724292 0.58885669 0.73794929]
  [0.51417471 0.81165201 0.91994261 0.02474345 0.80619796]
  [0.96855789 0.91635793 0.00951753 0.08579405 0.58610143]]]

numpy random randn

The Python Numpy randn function generates random arrays of one, 2D, and 3D Arrays.

import numpy as np
 
arr = np.random.randn(5)
 
print('-----Generated Random Array----')
print(arr)
 
arr2 = np.random.randn(8)
print('\n-----Generated Random Array----')
print(arr2)

The Python numpy random randn function output

-----Generated Random Array----
[ 0.83523213 -1.01096736 -0.7414885 2.09988314 0.91615544]

-----Generated Random Array----
[-1.38702799 1.38481935 -2.72106855 -0.36215012 -2.37834684 2.03501968
-0.47954383 -1.32138939]

This time we are generating two dimensional and three-dimensional arrays using the Numpy random randn function.

import numpy as np
 
arr = np.random.randn(5, 4)
 
print('-----Generated Two Dimensional Random Array----')
print(arr)
 
arr2 = np.random.randn(2, 3, 5)
print('\n-----Generated Three Dimensional Random Array----')
print(arr2)

numpy Array using random function

We are using the Numpy random function available in the module to generate an array of numbers of length 6 and 8

import numpy as np
 
arr = np.random.random(5)
 
print('-----Generated Random Array----')
print(arr)
 
arr2 = np.random.random((4, 5)) # Array size 4 * 5
print('\n-----Generated Two Dimensional Random Array----')
print(arr2)
 
arr3 = np.random.random((2, 3, 5)) # Array size 2 * 3 * 5
print('\n-----Generated Three Dimensional Random Array----')
print(arr3)

The Numpy random function output

-----Generated Random Array----
[0.64137581 0.52893567 0.97619638 0.58440911 0.02690007]

-----Generated Two Dimensional Random Array----
[[0.80152396 0.57538786 0.66899029 0.38246115 0.33088933]
[0.4770973 0.50341904 0.37849585 0.23645669 0.27725212]
[0.80437494 0.21056882 0.30182026 0.05074108 0.45707601]
[0.01345951 0.67492805 0.58910196 0.50513836 0.74921775]]

-----Generated Three Dimensional Random Array----
[[[0.97499028 0.65040763 0.40997138 0.8118288 0.81487291]
[0.49658275 0.09282607 0.83938535 0.45125944 0.3039278 ]
[0.73293826 0.78006654 0.5849649 0.87548218 0.83538677]]

[[0.85536797 0.45816044 0.78535175 0.94308075 0.10670098]
[0.70658212 0.13714645 0.0630409 0.93133062 0.30178682]
[0.60449303 0.02822692 0.71913424 0.99570444 0.61137136]]]

Python Numpy random randint

The Numpy random randint function returns an integer array from low value to high value of given size. The syntax of this Numpy function in Python is.

numpy.random.randint(low, high = None, size = None, type = ‘l’)

Let us see the Python Numpy random randint function example

import numpy as np
 
arr = np.random.randint(0, 5, size = 4)
 
print('-----Generated Random Array----')
print(arr)
 
arr2 = np.random.randint(10, 50, size = (5, 10))
print('\n-----Generated Two Dimensional Random Array----')
print(arr2)
 
arr3 = np.random.randint(1, 40, size = (2, 3, 7))
print('\n-----Generated Three Dimensional Random Array----')
print(arr3)

Python Numpy random randint function output

-----Generated Random Array----
[2 4 1 2]

-----Generated Two Dimensional Random Array----
[[19 39 22 48 21 34 46 39 12 15]
[43 21 20 28 48 29 28 15 29 17]
[36 28 30 35 17 44 33 38 11 18]
[17 15 28 33 20 33 24 33 10 11]
[25 33 37 44 42 20 24 39 24 14]]

-----Generated Three Dimensional Random Array----
[[[19 21 23 9 15 15 16]
[21 26 4 13 2 28 23]
[29 23 31 19 38 10 2]]

[[22 8 39 22 8 3 34]
[30 2 37 37 3 24 11]
[13 32 15 20 24 13 3]]]

Python Numpy random normal

The Python Numpy random normal function generates numbers from a normal distribution. This Numpy normal accepts the size of an array then fills that array with normally distributed values.

import numpy as np
 
arr = np.random.normal(size = 4)
 
print('-----Generated Random Array----')
print(arr)
 
arr2 = np.random.normal(size = (5, 5))
print('\n-----Generated Two Dimensional Random Array----')
print(arr2)
 
arr3 = np.random.normal(size = (2, 3, 4))
print('\n-----Generated Three Dimensional Random Array----')
print(arr3)

The Numpy random normal function output

-----Generated Random Array----
[-1.66160437 0.43505717 -0.74522529 0.34173931]

-----Generated Two Dimensional Random Array----
[[ 0.72445103 1.36516852 -1.59542701 -0.10782248 -0.59504893]
[-1.19228485 -0.6238485 1.46698494 -0.38137906 0.59017025]
[ 0.51707764 1.49834983 -0.54709123 -0.15535543 -0.87678266]
[ 1.346151 0.25772929 -0.00213373 0.58543647 -0.35374876]
[-0.39468152 0.96079429 -1.17187586 0.16560043 0.4487743 ]]

-----Generated Three Dimensional Random Array----
[[[ 0.99622715 -1.0571159 -0.11373001 1.19205186]
[ 1.39198314 -0.50049901 -1.42638241 -0.14458897]
[-1.5632502 0.41946535 1.11285195 0.90216863]]

[[ 0.45639877 0.34153265 1.63991247 0.49005306]
[-0.00269497 0.71291156 -0.17187131 -0.05854396]
[-0.23710731 -2.21511024 0.31094798 -1.01123501]]]

Python Numpy random uniform

The Numpy random uniform function generates a uniform distribution of numbers. This uniform accepts the array size and fills that array with uniform distributed values.

import numpy as np
 
arr = np.random.uniform(size = 5)
 
print('-----Generated Random Array----')
print(arr)
 
arr2 = np.random.uniform(size = (5, 5))
print('\n-----Generated Two Dimensional Random Array----')
print(arr2)
 
arr3 = np.random.uniform(size = (2, 3, 4))
print('\n-----Generated Three Dimensional Random Array----')
print(arr3)

The Python Numpy random uniform function output.

-----Generated Random Array----
[0.86094927 0.63186883 0.39364783 0.32536411 0.52483433]

-----Generated Two Dimensional Random Array----
[[0.88119145 0.51605353 0.26713714 0.34346039 0.34707231]
[0.15778072 0.39243675 0.9420596 0.5071728 0.51497773]
[0.78287236 0.00228852 0.48127646 0.27556824 0.18581121]
[0.72273377 0.98540534 0.38654194 0.78345594 0.20423307]
[0.87925609 0.9183766 0.11937258 0.98181138 0.25497945]]

-----Generated Three Dimensional Random Array----
[[[0.74953189 0.16232027 0.51204284 0.45291307]
[0.37186809 0.03543589 0.9230671 0.35753014]
[0.41904844 0.82840975 0.7316515 0.29189283]]

[[0.94959779 0.54924972 0.15773098 0.38614272]
[0.2739566 0.70382872 0.10895882 0.20279987]
[0.48210976 0.87194087 0.50062708 0.03436968]]]