python取素数

def prime_list(a):
    b=[1]
    for i in range(2,int(a**0.5)+1):
        b+=[m*i for m in range(i,a//i+1)]
    sa=set(range(1,a+1))
    sb=set(b)
    prime=sorted(list(sa-sb))
    return prime

import time
t1=time.time()
mm=len(prime_list(10000000))
t2=time.time()
print(mm)
print('耗时：',t2-t1)

返回
664579
耗时： 18.870527267456055