Fastest-in term of space- way to find prime numbers with python

Question

Maybe it is a stupid question, but i was wondering if you could provide the shortest source to find prime numbers with Python. I was also wondering how to find prime numbers

Answer 1

This uses more characters, but it's readable:

def primes_to(n):
    cands = set(xrange(2, n))
    for i in xrange(2, int(n ** 0.5) + 1):
        for ix in xrange(i ** 2, n, i):
            cands.discard(ix)
    return list(cands) 

EDIT

A new way, similar to the above, but with less missed attempts at discard:

def primes_to(n):
    cands = set(xrange(3, n, 2))
    for i in xrange(3, int(n ** 0.5) + 1, 2):
        for ix in xrange(i ** 2, n, i * 2):
            cands.discard(ix)
    return [2] + list(cands)