sieve_eratosthenes.py

# Purpose of this is to find primes from [2,n]

# Programmed by Aladdin Persson <aladdin.persson at hotmail dot com>
#   2019-02-27 Initial programming


def eratosthenes(n):
    primes, sieve = [], [True] * (n + 1)
    sieve[0], sieve[1] = "Zero", "One"

    for num in range(2, n + 1):
        if sieve[num]:
            primes.append(num)

            # "Optimized" loop here because we dont have to go up 1,2,3,4 in this
            # we can jump num instead
            for i in range(num * num, n + 1, num):
                sieve[i] = False

    return primes


if __name__ == "__main__":
    n = 10 ** 6
    primes = eratosthenes(n)
    print(primes)