Python – Random range in a List

When you need to generate a list of random numbers within a specific range, Python's random.randrange() method combined with list comprehension provides an efficient solution.

Syntax

The random.randrange() function generates random integers within a specified range ?

random.randrange(start, stop, step)

• start − Starting value (inclusive)
• stop − Ending value (exclusive)
• step − Step size (optional, default is 1)

Basic Example

Generate 10 random numbers between 1 and 100 ?

import random

my_result = [random.randrange(1, 100, 1) for i in range(10)]

print("The result is :")
print(my_result)

The result is :
[40, 73, 58, 45, 68, 19, 86, 6, 15, 71]

Different Range Examples

Even Numbers Only

Generate random even numbers by using step=2 ?

import random

even_numbers = [random.randrange(2, 21, 2) for i in range(5)]
print("Random even numbers:", even_numbers)

Random even numbers: [14, 8, 18, 6, 12]

Negative Range

Generate random numbers in negative range ?

import random

negative_numbers = [random.randrange(-50, 0) for i in range(5)]
print("Random negative numbers:", negative_numbers)

Random negative numbers: [-23, -41, -7, -35, -18]

Using Different Methods

Using random.randint()

Alternative approach with randint() which includes both endpoints ?

import random

# randint includes both start and end values
random_list = [random.randint(1, 100) for i in range(8)]
print("Using randint():", random_list)

Using randint(): [45, 89, 23, 67, 12, 91, 34, 76]

Comparison

How It Works

• The random module is imported to access random number functions
• List comprehension iterates the specified number of times
• randrange(1, 100, 1) generates random integers from 1 to 99 (100 is excluded)
• Each iteration produces a new random number added to the list

Conclusion

Use random.randrange() with list comprehension to generate lists of random numbers within specific ranges. This method offers flexibility with step values and precise range control for various random number generation needs.