python之多线程执行和非线程执行的对比
一、非线程执行（普通的执行）1、非线程运行，简单代码如下
#_*_coding:utf-8_*_
import time
import threading
a = []
b = []
def func1():
print "func1 start %s" % time.ctime()
alist = ["192.168.1.100","192.168.1.120","192.168.1.134","192.168.1.213"]
for i in alist:
a.append(i)
time.sleep(3)
def func2():
print "func2 start %s" % time.ctime()
blist = ["pc1","pc2","pc45","pc23"]
for i in blist:
b.append(i)
time.sleep(2)
func1()
func2()
print a,b
2、执行结果
/usr/bin/python2.7 /home/toby/PycharmProjects/SOMS/test.py
func1 start Tue Feb 28 03:03:44 2017
func2 start Tue Feb 28 03:03:47 2017
['192.168.1.100', '192.168.1.120', '192.168.1.134', '192.168.1.213'] ['pc1', 'pc2', 'pc45', 'pc23']
3、对执行结果简单分析
3分44秒运行函数func1，运行完之后，那么在3分47秒开始运行函数func2。也就是说这是典型的顺序执行。
二、多线程运行
1、多线程的代码如下
#_*_coding:utf-8_*_
import time
import threading
a = []
b = []
def func1():
print "func1 start %s" % time.ctime()
alist = ["192.168.1.100","192.168.1.120","192.168.1.134","192.168.1.213"]
for i in alist:
a.append(i)
time.sleep(3)
def func2():
print "func2 start %s" % time.ctime()
blist = ["pc1","pc2","pc45","pc23"]
for i in blist:
b.append(i)
time.sleep(2)
thr = []
t1 = threading.Thread(target=func1,)
thr.append(t1)
t2 = threading.Thread(target=func2,)
thr.append(t2)
for i in thr:
i.setDaemon(True)
i.start()
t1.join()
t2.join()
print a,b
2、多线程执行结果
/usr/bin/python2.7 /home/toby/PycharmProjects/SOMS/test.py
func1 start Tue Feb 28 03:09:32 2017
func2 start Tue Feb 28 03:09:32 2017
['192.168.1.100', '192.168.1.120', '192.168.1.134', '192.168.1.213'] ['pc1', 'pc2', 'pc45', 'pc23']
3、执行结果简单分析
线程t1调用函数func1，线程t2调用函数func2，根据运行时间来看，这两个线程是在同一时间运行。
注意：
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。 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。不然，会由于主线程执行完结束，从而导致子线程也终止。
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