python质数如何判断

import math

def isPrime(n):

  if n <= 1:

  return False

  for i in range(2, int(math.sqrt(n)) + 1):

  if n % i == 0:

    return False

  return True

from math import sqrt

N = 100

[ p for p in  range(2, N) if 0 not in [ p% d for d in range(2, int(sqrt(p))+1)] ]

from itertools import count

def isPrime(n): www.jb51.net

  if n <= 1:

    return False

  for i in count(2):

    if i * i > n:

      return True

    if n % i == 0:

      return False

def isPrime(n):

  if n <= 1:

    return False

  i = 2

  while i*i <= n:

    if n % i == 0:

      return False

    i += 1

  return True

def isPrime(n):

  if n <= 1:

    return False

  if n == 2:

    return True

  if n % 2 == 0:

    return False

  i = 3

  while i * i <= n:

    if n % i == 0:

      return False

    i += 2

  return True

#!/usr/bin/python

L1=[]

for x in xrange(20001,40001):

 n = 0

 for y in xrange(1,x+1):

 if x % y == 0:

  n = n + 1

 if n == 2 :

 print x

 L1.append(x)

print L1

20011

20021

20023

20029

20047

20051

20063

20071

20089

20101

20107

20113

20117

20123

20129

20143

20147

20149

20161

20173

….