prime_gaps.py

prime_gaps.py

import unittest

def gap(g,m,n):
    primes = []

    # finds primes in range
    for num in xrange(m,n+1,1): # n to be included in range
        x_half = num / 2
        is_prime = all(num % x != 0 for x in xrange(2,x_half+1,1))
        if is_prime == True:
            primes.append(num)

    for idx, prime in enumerate(primes):
        try:
            diff = primes[idx+1] - prime
            if diff == g:
                return tuple([prime, primes[idx+1]])
        except IndexError:
            return None


# gap(6,100,110)

class Test(unittest.TestCase):

    def test(self):
        self.assertEqual(gap(2,100,110), (101, 103))
        self.assertEqual(gap(4,100,110), (103, 107))
        self.assertEqual(gap(6,100,110), None)
        self.assertEqual(gap(8,300,400), (359, 367))
        self.assertEqual(gap(10,300,400), (337, 347))


if __name__ == '__main__':
    unittest.main()