Phython-守护线程

import threading,time

def run(n):
    print("task is ",n)
    time.sleep(2)
    print("task done", n)
start_time =time.time()
t_objs = []#存线程实例

for i in range(50):
    t = threading.Thread(target=run,args=("t-%s"%i,))
    t.setDaemon(True)#设为守护进程
    t.start()
    t_objs.append(t)
#for t in t_objs:
    #t.join()
#第二个参数查看是否是主线程还是子线程，第三个参数是查看活动线程
print("all threads has finished",threading.current_thread(),threading.active_count())
print("cost:",time.time()-start_time)