[find_primes] Several find primes method, Yield, Use sieve of eratosthenes to find primes. #python #math

find_primes.py

# Method 1  # sieve of eratosthenes
def primes(n): 
    i, p, ps, m = 0, 3, [2], n // 2
    sieve = [True] * m
    while p <= n:
        if sieve[i]:
            ps.append(p)
            for j in range(int((p*p-3)/2), m, p):
                sieve[j] = False
        i, p = i+1, p+2
    return ps
  

# Method 2 # Yield
def check_prime(n):
    for divisor in range(2, int(n ** 0.5) + 1):
        if n % divisor == 0:
            return False
    return True
        

def Primes(max):
    number = 1
    while number < max:
        number += 1
        if check_prime(number):
            yield number
            
list(Primes(1000))