setDaemon(True)方法

'''知识补充---for循环没有作用域'''
# s = 'abcdef'
# a = 0
# for i in s:
#  a+=1
# print(i=='f') # 循环最后一次i指向的是f，a是6
# print(a==6)


import threading
import time

'''
setDaemon(True)：将线程声明为守护线程，必须在start()方法调用之前设置。这个方法基本和join是相反的。
当我们在程序运行中，执行一个主线程，如果主线程又创建一个子线程，主线程和子线程就分兵两路，分别运行，那么当主线程完成
想退出时，会检验子线程是否完成。如果子线程未完成，则主线程会等待子线程完成后再退出。但是有时候我们需要的是只要主线程
完成了，不管子线程是否完成，都要和主线程一起退出，这时就可以用setDaemon()方法
'''
def music():
   print('begin to listen music %s' % time.ctime())
   time.sleep(3)
   print('stop to listen music %s' % time.ctime())

def game():
   print('begin to play game %s' % time.ctime())
   time.sleep(5)
   print('stop to play game %s' % time.ctime())

l = []

t1 = threading.Thread(target=music)
t2 = threading.Thread(target=game)

l.append(t1)
l.append(t2)

# if __name__ == '__main__':
#  for i in l:
#     i.setDaemon(True) # 一定要在所有start()之前设置
#  for t in l:
#     t.start()
#  print('ending...')
# begin to listen music Tue Jun  1 18:05:33 2021
# begin to play game Tue Jun  1 18:05:33 2021
# ending...

# if __name__ == '__main__':
#  t1.setDaemon(True)
#  for t in l:
#     t.start()
#  print('ending...')
# begin to listen music Tue Jun  1 18:06:49 2021
# begin to play game Tue Jun  1 18:06:49 2021
# ending...
# stop to listen music Tue Jun  1 18:06:52 2021
# stop to play game Tue Jun  1 18:06:54 2021

# if __name__ == '__main__':
#  t2.setDaemon(True)
#  for t in l:
#     t.start()
#  print('ending...')
# begin to listen music Tue Jun  1 18:08:13 2021
# begin to play game Tue Jun  1 18:08:13 2021
# ending...
# stop to listen music Tue Jun  1 18:08:16 2021

'''其它方法'''
# if __name__ == '__main__':
   # t1.run() # 线程被cpu调度后自动执行线程对象的run方法

   # t1.start()

   # print(t1.is_alive()) # 判断线程是否在运行

   # print(t1.getName()) # Thread-1
   # print(t2.getName()) # Thread-2

   # t1.setName('第一个线程')
   # print(t1.getName()) # 第一个线程