sieve.py

from time import time

def euler_sieve(n):
    # source: http://en.wikipedia.org/wiki/Sieve_of_Eratosthenes
    # Create a candidate list within which non-primes will
    # marked as None, noting that only candidates below
    # sqrt(n) need be checked. 
    candidates = range(n+1)
    fin = int(n**0.5)
 
    # Loop over the candidates, marking out each multiple.
    # If the current candidate is already checked off then
    # continue to the next iteration.
    for i in xrange(2, fin+1):
        if not candidates[i]:
            continue
 
        candidates[2*i::i] = [None] * (n//i - 1)
 
    # Filter out non-primes and return the list.
    return [i for i in candidates[2:] if i]

def print_sieve_info(n):
    start = time()
    primes = euler_sieve(n)
    stop = time()
    print('n = {0}'.format(n))
    print('sum: {0}'.format(sum(primes)))
    print('Final time: {0}'.format(stop-start))

print_sieve_info(200)
print_sieve_info(200000)