Python3 多线程 学习 threading

#-*- coding:utf-8 --*-
#多线程测试

import time
import datetime
import threading

def worker():

print("未用多线程")
time.sleep(1)

return

def worker2():
print("使用多线程")
time.sleep(1)
return

if __name__ == "__main__"    :
d1 = datetime.datetime.now()
for i in range(5):
worker()
d2 = datetime.datetime.now()
print(d2-d1)

d1 = datetime.datetime.now()
for j in range(5):
t = threading.Thread(target = worker2)
t.start()
d2 = datetime.datetime.now()
print(d2 - d1)
print("current has %d threads" % (threading.activeCount() - 1))