Prime numbers and shit.

primes.py

from time import clock
import sys

def percentageCompleted(cur, tot):
    p = (cur + .0) / (tot + .0) * 100
    return "%.2f" % p
    

def isPrime(num):
    if num <= 1:
        return ""
    elif num == 2:
        return "2\n"
    else:
        for x in xrange(2, num/2):
            if num % x == 0:
                return ""
        return str(num) + "\n"
        
f = file("./primes.txt", "w")
f.write("2\n")

def checkPrimes(upTo):
    x = 0
    for x in xrange(3, upTo + 1, 2):
        f.write( isPrime(x) )
        x = x + 1
        if x % 1000 == 0:
            s = percentageCompleted(x, upTo) + "%\t\t" + ( "%.2fs\r" % clock() )
            sys.stdout.write(s)
        
    f.close()

if __name__ == "__main__":
    checkPrimes(999999)
    x = raw_input()