Random

Python · Reference cheat sheet

📋 Overview

The random module provides pseudo-random numbers for simulations, sampling, and shuffling. Do not use it for security (passwords, tokens) — use secrets instead.

🔧 Core concepts

💡 Examples

import random

random.seed(42)
print(random.randint(1, 6))
print(random.choice(["red", "green", "blue"]))

deck = list(range(1, 53))
random.shuffle(deck)
hand = random.sample(deck, 5)

import random

# Weighted picks
colors = ["common", "rare", "epic"]
print(random.choices(colors, weights=[80, 15, 5], k=3))

import secrets

token = secrets.token_urlsafe(16)
code = secrets.randbelow(1_000_000)

⚠️ Pitfalls

• random is not cryptographically secure — use secrets for auth material.
• shuffle mutates the list; copy first if you need the original order.
• Global RNG is shared — prefer random.Random() in libraries/tests.
• Seeding makes runs reproducible but predictable.

🔗 Related

• hashlib
• statistics
• lambda
• lists