Primes

# See 'foundPrimes.txt' for what is loaded/saved in this code on each run

def isPrime(integer):
    global primes;

    for i in range(0,len(primes)):
        if(integer%int(primes[i])==0):
            return False;

    return True;

def printList(list):
    elements = 0;
    for i in list:
        print i,
        if(elements==10):
            elements = 0;
            print;
        elements += 1;

def listToString(list):
    output = "";
    for i in list:
        output += str(i) + " ";
    return output[0:len(output)-1];

print;

foundPrimes = open('foundPrimes.txt', 'r');
print 'Previously found primes:';
primes = foundPrimes.read().split(' ');
printList(primes);
print;
foundPrimes.close();

start = int(primes[len(primes)-1]);
limit = 100001;

for i in range(start, start+limit, 2):
    if(isPrime(i)):
        primes.append(i);

print '\nUpdated found primes:';
printList(primes);

foundPrimes = open('foundPrimes.txt', 'w');
foundPrimes.write(listToString(primes));
foundPrimes.close();