def givePrimeAt(index=100001): #// my first simple algorithm
if (index < 1 or isinstance(index, float)):
return -1
if index == 1:
return 2
prime_numbers = [2, 3]
i = 1
while len(prime_numbers) < index:
prime_number = giveNextPrimeAt(i)
isPrime(prime_number) and prime_numbers.append(prime_number)
i += 1
return prime_numbers[index - 1]
def getNthPrime(N=100001): #//another as efficient as above
if N == 1:
return 2
index, primeNumber = 1, 3
while index < N:
if isPrime(primeNumber):
index += 1
primeNumber += 2
return primeNumber - 2
def test_isPrime_returns_False_for_any_even_number_greater_than_2(self):
self.assertFalse(isPrime(4))
self.assertFalse(isPrime(100))
self.assertFalse(isPrime(12345678908))
def test_isPrime_returns_True_for_2(self):
self.assertTrue(isPrime(2))
def test_isPrime_returns_True_for_prime_number(self):
self.assertTrue(isPrime(3))
self.assertTrue(isPrime(103))
self.assertTrue(isPrime(6857))
def test_isPrime_returns_False_for_35_and_81(self):
self.assertFalse(isPrime(35))
self.assertFalse(isPrime(81))
def test_isPrime_returns_True_for_104743(self):
self.assertTrue(isPrime(104743))
def test_isPrime_returns_False_for_negative_number(self):
self.assertFalse(isPrime(-1))
def test_isPrime_returns_False_for_1(self):
self.assertFalse(isPrime(1))