generate_primes.py

import math
import itertools

def is_prime_alpha(n):
    if n < 2:
        return False
    i = 2
    while (i * i <= n):
        if n % i == 0:
            return False
        i = i + 1
    return True

def is_prime_beta(n):
    if n < 2:
        return False
    for i in range(2, int(math.sqrt(n)) + 1):
        if n % i == 0:
            return False
    return True

def is_prime_gamma(n):
    if n < 2:
        return False
    return not any(n % i == 0 for i in range(2, int(math.sqrt(n)) + 1))

def is_prime_delta(n):
    if n < 2:
        return False
    return all(n % i for i in range(2, int(math.sqrt(n)) + 1))


def is_prime(n):
    return is_prime_delta(n)

def n_prime_alpha(n):
    i = 2
    while n > 0:
        if is_prime(i):
            n = n - 1
            if n == 0:
                return i
        i = i + 1
    return -1

def n_prime_beta(n):
    cand = 1
    for i in range(n):
        cand += 1
        while not is_prime(cand):
            cand += 1
    return cand

def n_prime_gamma(n):
    return nth(yield_primes(), n - 1)

def yield_primes(beg=0):
    """Yields prime number by checking them individually - not efficient."""
    for i in itertools.count(beg):
        if is_prime(i):
            yield i

def nth(iterable, n, default=None):
    """Returns the nth item or a default value.
    From http://stackoverflow.com/questions/12007820/better-ways-to-get-nth-element-from-an-unsubscriptable-iterable ."""
    return next(itertools.islice(iterable, n, None), default)

def n_prime(n):
    return n_prime_gamma(n)

print(n_prime(10001))

thanks!