safe enough 8-character short unique random string

Question

I am trying to compute 8-character short unique random filenames for, let\'s say, thousands of files without probable name collision. Is this method safe enough?

Answer 1

Which method has less collisions, is faster and easier to read?

TLDR

The random.choice() is a bit faster, has about 3 orders of magnitude less collisions but is IMO slightly harder to read.

import string   
import uuid
import random

def random_choice():
    alphabet = string.ascii_lowercase + string.digits
    return ''.join(random.choices(alphabet, k=8))

def truncated_uuid4():
    return str(uuid.uuid4())[:8]

Test collisions

def test_collisions(fun):
    out = set()
    count = 0
    for _ in range(1000000):
        new = fun()
        if new in out:
            count += 1
        else:
            out.add(new)
    print(count)

test_collisions(random_choice)
test_collisions(truncated_uuid4)

Results on a single run with 10 million draws of 8-char uuids from the set abcdefghijklmnopqrstuvwxyz0123456789. Random choice vs truncated uuid4:

• collisions: 17 - 11632
• time (seconds): 37 - 63