素数的算法

[python]代码库

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

def main():
    f = open('C:/py/isprimes.txt', 'w')
    for n in primes():
        if n < 10000000000:
            f.write(str(n)+'. ')
        else:
            break
    f.close()

def _odd_iter():
    n = 1
    while True:
        n = n + 2
        yield n

def _not_divisible(n):
    
    return lambda x: x % n > 0

def primes():
    yield 2
    it = _odd_iter() #初始序列：奇数序列 it是一个生代器
    print('type it',type(it))
    print('it',it)
    while True:
        n = next(it) #返回序列的第一个数
        yield n
        it = filter(_not_divisible(n), it) #构造一个新的序列

if __name__ == '__main__':
    print(__name__)
    print('__main__')
    main()