Prime testing

eratosthenes.py

def test2(x):
    """ Sieve of Eratosthenes """
    p = []
    mask = range(2,x-1)
    
    while len(mask)>0:
        p.append(mask[0])
        del mask[::p[-1]]
        
    return p

naive_prime.py

def test1(x):
    """ Naive testing by divisibility """
    p = [2,3,5,7]
    for i in xrange(7,x-1):
        isprime = True
        for pi in p:
            isprime = ( isprime and (i%pi) )
            if not isprime: break
        if isprime: p.append(i)    
    return p