Generate password in python

Question

I'dl like to generate some alphanumeric passwords in python. Some possible ways are:

import string
from random import sample, choice
chars = string.letters + string.digits
length = 8
''.join(sample(chars,length)) # way 1
''.join([choice(chars) for i in range(length)]) # way 2

But I don't like both because:

• way 1 only unique chars selected and you can't generate passwords where length > len(chars)
• way 2 we have i variable unused and I can't find good way how to avoid that

So, any other good options?

P.S. So here we are with some testing with timeit for 100000 iterations:

''.join(sample(chars,length)) # way 1; 2.5 seconds
''.join([choice(chars) for i in range(length)]) # way 2; 1.8 seconds (optimizer helps?)
''.join(choice(chars) for _ in range(length)) # way 3; 1.8 seconds
''.join(choice(chars) for _ in xrange(length)) # way 4; 1.73 seconds
''.join(map(lambda x: random.choice(chars), range(length))) # way 5; 2.27 seconds

So, the winner is ''.join(choice(chars) for _ in xrange(length)).

Answer 1

You should use the secrets module to generate cryptographically safe passwords, which is available starting in Python 3.6. Adapted from the documentation:

import secrets
import string
alphabet = string.ascii_letters + string.digits
password = ''.join(secrets.choice(alphabet) for i in range(20))  # for a 20-character password

For more information on recipes and best practices, see this section on recipes in the Python documentation. You can also consider adding string.punctuation or even just using string.printable for a wider set of characters.