#! /usr/bin/env python
#coding=utf-8
# FIlename ex1.py
import threading
from time import sleep
def test_func(id):
	for i in range(0,5):
		sleep(1)
		print('thread %d is running %d' % (id,i))
threads = []
for i in range(0,3):
	t = threading.Thread(target = test_func ,args=(i,))
	threads.append(t)
for t in threads:
	t.start()
for t in threads:
	t.join()

输出结果：

thread 0 is running 0
thread 1 is running 0
thread 2 is running 0
thread 0 is running 1
thread 1 is running 1
thread 2 is running 1
thread 0 is running 2
thread 1 is running 2
thread 2 is running 2
thread 0 is running 3
thread 1 is running 3
thread 2 is running 3
thread 0 is running 4
thread 1 is running 4
thread 2 is running 4
[Finished in 5.2s]

从输出结果可以看到，3个线程是交替的执行的