Python - Generate Random String of given Length

Last Updated : 07 Jan, 2025

Generating random strings is a common requirement for tasks like creating unique identifiers, random passwords, or testing data. Python provides several efficient ways to generate random strings of a specified length. Below, we’ll explore these methods, starting from the most efficient.

Using random.choices()

This method from Python’s random module is optimized for generating random sequences from a given set of characters.

Python

import random
import string

length = 8
random_string = ''.join(random.choices(string.ascii_letters + string.digits, k=length))
print(random_string)

Output

Ri7CHq8V

Explanation:

string.ascii_letters includes both uppercase and lowercase alphabets.
string.digits adds numeric characters to the pool.
random.choices() selects characters randomly based on the specified length (k).
join combines the list of characters into a single string.

Let's explore different ways to generate random string of given length.

Table of Content

Using the secrets Module

For secure applications, the secrets module offers a higher level of randomness suitable for cryptographic purposes.

Python

import secrets
import string

length = 8
random_string = ''.join(secrets.choice(string.ascii_letters + string.digits) for _ in range(length))
print(random_string)

Output

YEYLR2TI

Explanation:

secrets.choice randomly selects a character securely from the given pool.
The list comprehension iterates for the desired length to build the string.
This method is ideal for generating passwords or secure tokens.

Using the uuid Module

The uuid module can generate universally unique identifiers (UUIDs), which can be trimmed to a desired length.

Python

import uuid

length = 8
random_string = str(uuid.uuid4()).replace('-', '')[:length]
print(random_string)

Output

12578bc5

Explanation:

uuid.uuid4 generates a random UUID.
replace removes dashes from the UUID string.
Slicing ensures the string matches the required length.

Using os.urandom()

The os.urandom function generates secure random bytes, which can be converted to a readable string.

Python

import os
import base64

length = 8
random_string = base64.b64encode(os.urandom(length)).decode('utf-8')[:length]
print(random_string)

Output

NsqJ/Ll1

Explanation:

os.urandom generates random bytes.
base64.b64encode converts these bytes into a string.
Slicing limits the string to the desired length.

Using a Manual Loop with random

For simplicity, a manual loop with the random module can also generate random strings.

Python

import random
import string

length = 8
random_string = ''.join([random.choice(string.ascii_letters + string.digits) for _ in range(length)])
print(random_string)