import time
Times=1000
def isPrime(n):
for i in range (2,int(n/2)+1):
if n%i==0:
return False
else:
return True
strPrimes=""
t=time.clock()
for j in range(2,Times):
if isPrime(j):
strPrimes=strPrimes+str(j)+" "
print("Time used:{}".format(time.clock()-t))
print(strPrimes)

求素数