What is random list in python?


There is a need to generate random numbers when studying a model or behavior of a program for different range of values. Python can generate such random numbers by using the random module. In the below examples we will first see how to generate a single random number and then extend it to generate a list of random numbers.

Generating a Single Random Number

The random() method in random module generates a float number between 0 and 1.

Example

import random
n = random.random()
print(n)

Output

Running the above code gives us the following result −

0.2112200

Generating Number in a Range

The randint() method generates a integer between a given range of numbers.

Example

import random
n = random.randint(0,22)
print(n)

Output

Running the above code gives us the following result −

2

Generating a List of numbers Using For Loop

We can use the above randint() method along with a for loop to generate a list of numbers. We first create an empty list and then append the random numbers generated to the empty list one by one.

Example

import random
randomlist = []
for i in range(0,5):
n = random.randint(1,30)
randomlist.append(n)
print(randomlist)

Output

Running the above code gives us the following result −

[10, 5, 21, 1, 17]

Using random.sample()

We can also use the sample() method available in random module to directly generate a list of random numbers.Here we specify a range and give how many random numbers we need to generate.

Example

import random
#Generate 5 random numbers between 10 and 30
randomlist = random.sample(range(10, 30), 5)
print(randomlist)

Output

Running the above code gives us the following result −

[16, 19, 13, 18, 15]

What is random list in python?

Updated on 08-Aug-2019 06:54:57

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Given a list and our task is to randomly select elements from the list in Python using various functions. Selecting random numbers from a list can be used sometimes while building games, choosing a random range, etc. 

Example :

Input: [2, 3, 4 , 5, 6 ]
Output: 2
Input: [3, 5, 6, 3, 2]
Output: 6

Using random.choice()  to select random value from a list

This random.choice() function is designed for getting a Random sampling from a list in Python and hence is the most common method to achieve this task of fetching a random number from a list. 

Python3

import random

test_list = [1, 4, 5, 2, 7]

print("Original list is : " + str(test_list))

random_num = random.choice(test_list)

print("Random selected number is : " + str(random_num))

Output:

Original list is : [1, 4, 5, 2, 7]
Random selected number is : 1

Using random.randrange() to select random value from a list

random.randrange() method is used to generate a random number in a given range, we can specify the range to be 0 to the length of the list, and get the index, and then the corresponding value.

Python3

import random

test_list = [1, 4, 5, 2, 7]

print("Original list is : " + str(test_list))

rand_idx = random.randrange(len(test_list))

random_num = test_list[rand_idx]

print("Random selected number is : " + str(random_num))

Output:

Original list is : [1, 4, 5, 2, 7]
Random selected number is : 7

Using random.randint() to select random value from a list

random.randint() is used to generate the random number, also this can be used to generate any number in a range, and then using that number, we can find the value at the corresponding index, just like the above-mentioned technique. But it differs by the fact that it requires 2 mandatory arguments for range. 

Python3

import random

test_list = [1, 4, 5, 2, 7]

print("Original list is : " + str(test_list))

rand_idx = random.randint(0, len(test_list)-1)

random_num = test_list[rand_idx]

print("Random selected number is : " + str(random_num))

Output:

Original list is : [1, 4, 5, 2, 7]
Random selected number is : 4

Using random.random() to select random value from a list

random.random() method generates the floating-point numbers in the range of 0 to 1. We can also get the index value of list using this function by multiplying the result and then typecasting it to integer so as to get the integer index and then the corresponding list value. 

Python3

import random

test_list = [1, 4, 5, 2, 7]

print("Original list is : " + str(test_list))

rand_idx = int(random.random() * len(test_list))

random_num = test_list[rand_idx]

print("Random selected number is : " + str(random_num))

Output:

Original list is : [1, 4, 5, 2, 7]
Random selected number is : 7

Using random.sample() to select random value from a list

Python has a built-in function called random.sample(). The random module contains the random.sample() function. It has the ability to choose multiple items from a list.

Python3

import random

test_list = [1, 4, 5, 2, 7]

print("Original list is : " + str(test_list))

print("Random element is :", random.sample(test_list, 5))

Output:

Original list is : [1, 4, 5, 2, 7]
Random element is : [7, 4, 1, 5, 2]

Using random.choices() to select random value from a list

The random.choices function is stored in the random module (). Selecting numerous items from a list or a single item from a particular sequence is handy with the help of random.choices function.

Python3

import random

test_list = [11, 44, 55, 22, 77]

print("Original list is : " + str(test_list))

print("Random element is :", random.choices(test_list, k=4))

Output:

Original list is : [11, 44, 55, 22, 77]
Random element is : [11, 11, 44, 77]

Select k random value from a list

Here we have grouped all elements in a pair of size k.

Python3

import random

def select_random_Ns(l, k):

    random.shuffle(l)

    res = []

    for i in range(0, len(l), k):

        res.append(l[i:i + k])

    return res

l = ['G', 'E', 'E', 'K', 'S', 'F', 'O', 'R', 'G', 'E', 'E', 'K', 'S']

print(select_random_Ns(l, 3))

Output:

[['G', 'G', 'R'], ['K', 'K', 'E'], ['O', 'F', 'E'], ['S', 'E', 'S'], ['E']]

How do you define a random list in Python?

Generating random number list in Python.
import random n = random. random() print(n).
import random n = random. randint(0,22) print(n).
import random randomlist = [] for i in range(0,5): n = random. randint(1,30) randomlist. ... .
import random #Generate 5 random numbers between 10 and 30 randomlist = random..

What is random in Python with example?

Python has a built-in module that you can use to make random numbers. ... Python Random Module..

Why random is used in Python?

Python offers random module that can generate random numbers. These are pseudo-random number as the sequence of number generated depends on the seed. If the seeding value is same, the sequence will be the same. For example, if you use 2 as the seeding value, you will always see the following sequence.