多线程的一点疑惑

赢在未来°

代码如下：

1. #!/usr/bin/env python
   
2. import threading
   
3. import time
   
4. 
   
5. 
   
6. class MyThread(threading.Thread):
   
7.     def __init__(self,event):
   
8.         threading.Thread.__init__(self)
   
9.         self.event = event
   
10. 
    
11.     def run(self):
    
12.         if not self.event.isSet():
    
13.             print '{0} is sleep...'.format(self.getName())
    
14.             self.event.wait()
    
15.             print '{0} is awaked!'.format(self.getName())
    
16. 
    
17. event = threading.Event()
    
18. event.clear()
    
19. 
    
20. thlist = []
    
21. 
    
22. for i in range(1,5):
    
23.     i = MyThread(event)
    
24.     thlist.append(i)
    
25. 
    
26. for i in thlist:
    
27. #    i.setDaemon(True)
    
28.     i.start()
    
29. print 'Sleep 1 second..'
    
30. time.sleep(1)
    
31. event.set()

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执行结果如下：

1. root@localhost:~# python --version
   
2. Python 2.7.3
   
3. root@localhost:~# python test.py
   
4. Thread-1 is sleep...
   
5. Thread-2 is sleep...
   
6. Thread-3 is sleep...
   
7. Sleep 1 second..
   
8. Thread-4 is sleep...
   
9. Thread-1 is awaked!
   
10. Thread-2 is awaked!
    
11. Thread-3 is awaked!
    
12. Thread-4 is awaked!

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最后一个线程为什么比主线程后执行呢？

赢在未来°

以下为猜测，不知道对不对~~~
大致有点懂了，因为每个线程的创建都需要开销，创建最后一个线程会花费一些开销，而这时主线程已经执行完了
代码可以这样改一下：

1. #!/usr/bin/env python
   
2. import threading
   
3. import time
   
4. 
   
5. 
   
6. class MyThread(threading.Thread):
   
7.     def __init__(self,event):
   
8.         threading.Thread.__init__(self)
   
9.         self.event = event
   
10. 
    
11.     def run(self):
    
12.         if not self.event.isSet():
    
13.             self.event.wait()
    
14.             print '{0} is awaked!'.format(self.getName())
    
15. 
    
16. event = threading.Event()
    
17. event.clear()
    
18. 
    
19. thlist = []
    
20. 
    
21. for i in range(1,5):
    
22.     i = MyThread(event)
    
23.     thlist.append(i)
    
24. 
    
25. for i in thlist:
    
26. #    i.setDaemon(True)
    
27.     print '{0} is start...'.format(i)
    
28.     i.start()
    
29. 
    
30. print 'Sleep 1 second..'
    
31. time.sleep(1)
    
32. 
    
33. event.set()

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1. root@localhost:~# python test.py
   
2. <MyThread(Thread-1, initial)> is start...
   
3. <MyThread(Thread-2, initial)> is start...
   
4. <MyThread(Thread-3, initial)> is start...
   
5. <MyThread(Thread-4, initial)> is start...
   
6. Sleep 1 second..
   
7. Thread-1 is awaked!
   
8. Thread-2 is awaked!
   
9. Thread-3 is awaked!
   
10. Thread-4 is awaked!

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