random.randint(a, b) gives a whole number from a to b, and both ends are included.
python
import random roll = random.randint(1, 6) print(roll)
example output · yours will differ
4
Yours will differ, which is the point. Press Run a few times.
The other things people need
python
import random print(random.random()) # a float from 0.0 up to (not including) 1.0 print(random.uniform(1.5, 3.5)) # a float in a range print(random.choice(["rock", "paper", "scissors"])) print(random.sample(range(1, 50), 6)) # 6 different numbers, no repeats deck = ["A", "K", "Q", "J", "10"] random.shuffle(deck) # shuffles in place, returns None print(deck)
example output · yours will differ
0.6394267984578837 2.0498536229468446 paper [33, 7, 48, 12, 25, 3] ['Q', 'A', '10', 'K', 'J']
Watch out for deck = random.shuffle(deck): shuffle changes the list where it is and returns None, so that line throws your deck away.
The same "random" numbers every time
For tests, simulations you want to repeat, or a bug you're chasing, set a seed. The same seed gives the same sequence on every run:
python
import random random.seed(42) print([random.randint(1, 100) for _ in range(5)]) random.seed(42) print([random.randint(1, 100) for _ in range(5)])
output
[82, 15, 4, 95, 36] [82, 15, 4, 95, 36]
Passwords, tokens and anything secret: use secrets
random is built to be fast and repeatable, and with enough of its output someone can predict the rest. For a password, a reset link or an API key, use secrets, which draws from the operating system's secure source:
python
import secrets import string alphabet = string.ascii_letters + string.digits password = "".join(secrets.choice(alphabet) for _ in range(16)) print(len(password), "characters") print(len(secrets.token_urlsafe(32)), "character reset token")
output
16 characters 43 character reset token
The password generator project builds a complete tool around this.