Python中的简单Prime生成器

有一些问题：

• 当计数不除以x时，为什么要打印计数？这并不意味着它是素数，仅意味着该特定x不会将其除

• continue

  移至下一个循环迭代-但你确实想使用停止它

  break

  
  这是你的代码，其中包含一些修复程序，它仅输出质数：
  

import mathdef main():    count = 3    while True:        isprime = True        for x in range(2, int(math.sqrt(count) + 1)): if count % x == 0:      isprime = False     break        if isprime: print count        count += 1

有关更有效的质子生成，请参见其他人的建议，参见戊二烯筛。这是一个不错的，经过优化的实现，带有很多注释：

# Sieve of Eratosthenes# Code by David Eppstein, UC Irvine, 28 Feb 2002# http://pre.activestate.com/recipes/117119/def gen_primes():    """ Generate an infinite sequence of prime numbers.    """    # Maps composites to primes witnessing their compositeness.    # This is memory efficient, as the sieve is not "run forward"    # indefinitely, but only as long as required by the current    # number being tested.    #    D = {}    # The running integer that's checked for primeness    q = 2    while True:        if q not in D: # q is a new prime. # Yield it and mark its first multiple that isn't # already marked in previous iterations #  yield q D[q * q] = [q]        else: # q is composite. D[q] is the list of primes that # divide it. Since we've reached q, we no longer # need it in the map, but we'll mark the next  # multiples of its witnesses to prepare for larger # numbers #  for p in D[q]:     D.setdefault(p + q, []).append(p) del D[q]        q += 1

请注意，它返回一个生成器。