Thread

 一、没有线程的支持的例子：

　　

#!/usr/bin/env python

from time import sleep,ctime

def loop0():
	print 'start loop 0 at:',ctime()
	sleep(4)
	print 'loop 0 done at:',ctime()

def loop1():
	print 'start loop 1 at:',ctime()
	sleep(2)
	print 'loop 1 done at:',ctime()

def main():
	print 'starting at:',ctime()
	loop0()
	loop1()
	print 'all Done at:',ctime()

if __name__ == '__main__':
	main()

　　运行结果

starting at: Sun Dec 20 15:27:45 2015
start loop 0 at: Sun Dec 20 15:27:45 2015
loop 0 done at: Sun Dec 20 15:27:49 2015
start loop 1 at: Sun Dec 20 15:27:49 2015
loop 1 done at: Sun Dec 20 15:27:51 2015
all Done at: Sun Dec 20 15:27:51 2015
[Finished in 6.0s]

　　在单线程中执行两个循环。当一个循环结束后，另一个才能开始。总时间是各个循环时间之和

 

二、thread

#!/usr/bin/env python

import thread
from time import sleep,ctime

def loop0():
	print 'start loop0 at:',ctime()
	sleep(4)
	print 'loop0 done at:',ctime()

def loop1():
	print 'start loop1 at:',ctime()
	sleep(2)
	print 'loop1 done at:',ctime()

def main():
	print 'starting at:',ctime()
	thread.start_new_thread(loop0,())
	thread.start_new_thread(loop1,())
	sleep(6)
	print 'all done at:',ctime()

if __name__ == '__main__':
	main()

　　运行结果：

starting at: Sun Dec 20 15:43:09 2015
start loop0 at: Sun Dec 20 15:43:09 2015
start loop1 at: Sun Dec 20 15:43:09 2015
loop1 done at: Sun Dec 20 15:43:11 2015
loop0 done at: Sun Dec 20 15:43:13 2015
all done at: Sun Dec 20 15:43:15 2015
[Finished in 6.0s]

　　注意：start_new_thread()要求一定要有前两个参数，所以，就算我们想要运行的函数不需要参数，我们也要传一个空的元组

　　睡眠的4秒和2秒代码现在是并发执行的，这样就使得总的运行时间被缩短了，可以看到loop1甚至再loop0之前就结束了，为什么要加上

　　sleep(6)？ 原因是：因为如果我们没有让主线程停下来，那么主线程就会运行下一条语句，显示『all done』,然后就关闭运行着loop0，loop1的两个线程

　　退出了。

 

三、使用线程和锁

#!/usr/bin/env python
#--*-- coding:utf-8 --*--

import thread
from time import sleep,ctime

loops = [4,2]

def loop(nloop,nsec,lock):
	print 'start loop',nloop,'at:',ctime()
	sleep(nsec)
	print 'loop',nloop,'done at:',ctime()
	lock.release()

def main():
	print 'starting at:',ctime()
	locks = []
	nloops = range(len(loops))

	for i in nloops:
		lock = thread.allocate_lock()
		lock.acquire()
		locks.append(lock)

	for i in nloops:
		thread.start_new_thread(loop,(i,loops[i],locks[i]))

	for i in nloops:
		while locks[i].locked():pass

	print 'all done at:',ctime()

if __name__ == '__main__':
	main()