Zhengfu's assignment #2

prime_num.py

from math import sqrt
from itertools import islice


def is_prime(num):
    if num in (2, 3):
        return True

    for factor in range(2, int(sqrt(num)) + 1):
        if num % factor == 0:
            return False
    return True


class prime_num_iterator:
    """An iterator that generates prime numbers."""
    
    def __init__(self):
        self.num = 1
        
    def __iter__(self):
        return self
            
    def __next__(self):
        while True:
            self.num += 1
            if is_prime(self.num):
                return self.num


def prime_num_generator():
    """An generator that generates prime numbers."""
    
    num = 2
    while True:
        if is_prime(num):
            yield num
        num += 1


if __name__ == "__main__":
    primes_1 = prime_num_iterator()
    primes_2 = prime_num_generator()

    # Use the islice() method to slice off the first 10 prime numbers, of course, any number of primes is fine.
    print(list(islice(primes_1, 0, 10)))
    print(list(islice(primes_2, 0, 10)))