Python Random Module

Python Random module is an in-built module of Python which is used to generate random numbers. These are pseudo-random numbers means these are not truly random. This module can be used to perform random actions such as generating random numbers, print random a value for a list or string, etc.

Example: Printing a random value from a list

Python3

# import random
import random

# prints a random value from the list
list1 = [1, 2, 3, 4, 5, 6]
print(random.choice(list1))

Output:

2

As stated above random module creates pseudo-random numbers. Random numbers depend on the seeding value. For example, if the seeding value is 5 then the output of the below program will always be the same.

Example: Creating random numbers with seeding value

Python3

import random

random.seed(5)

print(random.random())
print(random.random())

Output:

0.6229016948897019
0.7417869892607294

The output of the above code will always be the same. Therefore, it must not be used for encryption.

Let’s discuss some common operations performed by this module.

Creating Random Integers

random.randint() method is used to generate random integers between the given range.

Syntax :

randint(start, end)

Example: Creating random integers

Python3

# Python3 program explaining work
# of randint() function

# import random module
import random

# Generates a random number between
# a given positive range
r1 = random.randint(5, 15)
print("Random number between 5 and 15 is % s" % (r1))

# Generates a random number between
# two given negative range
r2 = random.randint(-10, -2)
print("Random number between -10 and -2 is % d" % (r2))

Output:

Random number between 5 and 15 is 7
Random number between -10 and -2 is -9

Creating Random Floats

random.random() method is used to generate random floats between 0.0 to 1.

Syntax: 

random.random()

Example:

Python3

# Python3 program to demonstrate
# the use of random() function .

# import random
from random import random

# Prints random item
print(random())

Output:

0.3717933555623072

Selecting Random Elements

random.choice() function is used to return a random item from a list, tuple, or string.

Syntax:

random.choice(sequence)

Example: Selecting random elements from the list, string, and tuple

Python3

# Python3 program to demonstrate the use of
# choice() method

# import random
import random

# prints a random value from the list
list1 = [1, 2, 3, 4, 5, 6]
print(random.choice(list1))

# prints a random item from the string
string = "geeks"
print(random.choice(string))

# prints a random item from the tuple
tuple1 = (1, 2, 3, 4, 5)
print(random.choice(tuple1))

Output:

2
k
5

Shuffling List

random.shuffle() method is used to shuffle a sequence (list). Shuffling means changing the position of the elements of the sequence. Here, the shuffling operation is inplace.

Syntax:

random.shuffle(sequence, function)

Example: Shuffling a List

Python3

# import the random module
import random


# declare a list
sample_list = [1, 2, 3, 4, 5]

print("Original list : ")
print(sample_list)

# first shuffle
random.shuffle(sample_list)
print("\nAfter the first shuffle : ")
print(sample_list)

# second shuffle
random.shuffle(sample_list)
print("\nAfter the second shuffle : ")
print(sample_list)

Output:

Original list : 
[1, 2, 3, 4, 5]

After the first shuffle : 
[4, 3, 5, 2, 1]

After the second shuffle : 
[1, 3, 4, 5, 2]

List of all the functions in Random Module

Function Name	Description
seed()	Initialize the random number generator
getstate()	Returns an object with the current internal state of the random number generator
setstate()	Used to restore the state of the random number generator back to the specified state
getrandbits()	Return an integer with a specified number of bits
randrange()	Returns a random number within the range
randint()	Returns a random integer within the range
choice()	Returns a random item from a list, tuple, or string
choices()	Returns multiple random elements from the list with replacement
sample()	Returns a particular length list of items chosen from the sequence
random()	Generate random floating numbers
uniform()	Return random floating number between two numbers both inclusive
triangular()	Return a random floating point number within a range with a bias towards one extreme
betavariate()	Return a random floating point number with beta distribution
expovariate()	Return a random floating point number with exponential distribution
gammavariate()	Return a random floating point number with gamma distribution
gauss()	Return a random floating point number with Gaussian distribution
lognormvariate()	Return a random floating point number with log-normal distribution
normalvariate()	Return a random floating point number with normal distribution
vonmisesvariate()	Return a random floating point number with von Mises distribution or circular normal distribution
paretovariate()	Return a random floating point number with Pareto distribution
weibullvariate()	Return a random floating point number with Weibull distribution