7.寻找素数

定义：除了1 和本身之外，不被任何数整除。 7 = 7*1   是     9 = 3*3 不是

代码：

#!/usr/bin/env python
# encoding: utf-8
"""
@author: 侠之大者kamil
@file: 8.素数.py
@time: 2016/4/9 18:25
"""
import math
def isPrimeNumber(n,s):
    #for k in range(2,int(math.sqrt(n)) + 1):
    for k in s:#s为小于n的素数的集合
        if k * k > n:break#保证k 小于n的平方根，for k in range(2,int(math.sqrt(n)) + 1)
        if n % k ==0 : return None #
    return n
prime=[]
for n in range(2,300):
    res = isPrimeNumber(n,prime)
    if res:
        prime.append(res)
print(prime)

结果：

ssh://kamil@192.168.16.128:22/usr/bin/python3 -u /home/kamil/py22/趣味百题/8.素数.py
[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293]

Process finished with exit code 0