':
? ? for t in threads:
? ? ? ? t.setDaemon(True)
? ? ? ? t.start()
? ?
? ? t.join()
? ? print "all over %s" %ctime()
我们只对上面的程序加了个join()方法，用于等待线程终止。join（）的作用是，在子线程完成运行之前，这个子线程的父线程将一直被阻塞。
注意:? join()方法的位置是在for循环外的，也就是说必须等待for循环里的两个进程都结束后，才去执行主进程。
运行结果：
>>> ========================= RESTART ================================
>>>
I was listening to 爱情买卖. Thu Apr 17 13:04:11 2014? I was at the 阿凡达! Thu Apr 17 13:04:11 2014
I was listening to 爱情买卖. Thu Apr 17 13:04:12 2014
I was at the 阿凡达! Thu Apr 17 13:04:16 2014
all over Thu Apr 17 13:04:21 2014
从执行结果可看到，music 和move 是同时启动的。
开始时间4分11秒，直到调用主进程为4分22秒，总耗时为10秒。从单线程时减少了2秒，我们可以把music的sleep()的时间调整为4秒。
...
def music(func):
? ? for i in range(2):
? ? ? ? print "I was listening to %s. %s" %(func,ctime())
? ? ? ? sleep(4)
...
执行结果：
>>> ====================== RESTART ================================
>>>
I was listening to 爱情买卖. Thu Apr 17 13:11:27 2014I was at the 阿凡达! Thu Apr 17 13:11:27 2014
I was listening to 爱情买卖. Thu Apr 17 13:11:31 2014
I was at the 阿凡达! Thu Apr 17 13:11:32 2014
all over Thu Apr 17 13:11:37 2014
子线程启动11分27秒，主线程运行11分37秒。
虽然music每首歌曲从1秒延长到了4 ，但通多程线的方式运行脚本，总的时间没变化。
本文从感性上让你快速理解python多线程的使用，更详细的使用请参考其它文档或资料。
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class threading.Thread()说明：
class threading.Thread(group=None, target=None, name=None, args=(), kwargs={})
This constructor should always be called with keyword arguments. Arguments are:
group should be None; reserved for future extension when a ThreadGroup class is implemented.
target is the callable object to be invoked by the run() method. Defaults to None, meaning nothing is called.
name is the thread name. By default, a unique name is constructed of the form “Thread-N” where N is a small decimal number.
args is the argument tuple for the target invocation. Defaults to ().
kwargs is a dictionary of keyword arguments for the target invocation. Defaults to {}.
If the subclass overrides the constructor, it must make sure to invoke the base class constructor (Thread.__init__()) before doing
anything else to the thread.