单线程
顾名思义，可以理解为把一堆事情排在一起，一件一件去做，例子如下：
比如我们回到家里，先写作业，在看书或者玩游戏娱乐一下。
from time import ctime, sleep
def homework():
for i in range(3):
print("i am doing homework.{}".format(ctime()))
sleep(3)
def play():
for i in range(2):
print("i am plaing.{}".format(ctime()))
sleep(2)
if __name__ == '__main__':
homework()
play()
print("all over.{}".format(ctime()))所显示结果如下：
i am doing homework.Tue Dec 4 16:53:22 2018
i am doing homework.Tue Dec 4 16:53:25 2018
i am doing homework.Tue Dec 4 16:53:28 2018
i am plaing.Tue Dec 4 16:53:31 2018
i am plaing.Tue Dec 4 16:53:33 2018
all over.Tue Dec 4 16:53:35 2018时间是逐渐叠加的，干完一件事再做另一件事。
多线程
而到了多线程就不一样了，同时可以做很多事情，就像分身一样。而python里，多线程模块主要由thread 和 threading两个库来实现。展示如下：
from time import ctime, sleep
import threading
def homework():
for i in range(3):
print("i am doing homework.{}".format(ctime()))
sleep(3)
def play():
for i in range(2):
print("i am plaing.{}".format(ctime()))
sleep(2)
threads=[]
t1=threading.Thread(target=homework)
threads.append(t1)
t2=threading.Thread(target=play)
threads.append(t2)
if __name__ == '__main__':
for t in threads:
t.setDaemon(True)
t.start()
显示结果如下：
i am doing homework.Tue Dec 4 17:01:09 2018
i am plaing.Tue Dec 4 17:01:09 2018
i am plaing.Tue Dec 4 17:01:11 2018
i am doing homework.Tue Dec 4 17:01:12 2018
i am doing homework.Tue Dec 4 17:01:15 2018在其中，我们可见首先倒入了threading模块，这是实现多线程的前提。同时创立了threads[]数组，利用target调用homework和play方法，同时可以利用args对所使用方法进行传递参数。并将创建好的线程t1装入到threads[]数组中，t2也采用同样的方法。
再通过for的方式进行遍历，setDaemon(True)将线程声明为守护线程，必须在start() 方法调用之前设置，如果不设置为守护线程程序会被无限挂起。子线程启动后，父线程也继续执行下去。
from time import ctime, sleep
import threading
def homework():
for i in range(3):
print("i am doing homework.{}".format(ctime()))
sleep(3)
def play():
for i in range(2):
print("i am plaing.{}".format(ctime()))
sleep(2)
threads=[]
t1=threading.Thread(target=homework)
threads.append(t1)
t2=threading.Thread(target=play)
threads.append(t2)
if __name__ == '__main__':
for t in threads:
t.setDaemon(True)
t.start()
t.join()
print('all over.{}'.format(ctime()))
加入t.join()之后，可见在其中一个子线程结束之后输出结果。结果如下：
i am doing homework.Tue Dec 4 17:09:53 2018
i am plaing.Tue Dec 4 17:09:53 2018
i am plaing.Tue Dec 4 17:09:55 2018
i am doing homework.Tue Dec 4 17:09:56 2018
all over.Tue Dec 4 17:09:57 2018
i am doing homework.Tue Dec 4 17:09:59 2018再加入一个例子
#coding=utf-8
from time import sleep, ctime
import threading
def muisc(func):
for i in range(2):
print ('Start playing： %s! %s' %(func,ctime()))
sleep(2)
def move(func):
for i in range(2):
print ('Start playing： %s! %s' %(func,ctime()))
sleep(5)
def player(name):
r = name.split('.')[1]
if r == 'mp3':
muisc(name)
else:
if r == 'mp4':
move(name)
else:
print ('error: The format is not recognized!')
list = ['ni.mp3','door.mp4']
threads = []
files = range(len(list))
#创建线程
for i in files:
t = threading.Thread(target=player,args=(list[i],))
threads.append(t)
if __name__ == '__main__':
#启动线程
for i in files:
threads[i].start()
for i in files:
threads[i].join()
#主线程
print ('end:%s' %ctime())显示结果如下：
Start playing： ni.mp3! Tue Dec 4 17:24:27 2018Start playing： door.mp4! Tue Dec 4 17:24:27 2018
Start playing： ni.mp3! Tue Dec 4 17:24:29 2018
Start playing： door.mp4! Tue Dec 4 17:24:32 2018
end:Tue Dec 4 17:24:37 2018当然，上面的例子还可以继续改进
from time import ctime, sleep
import threading
def super_player(file, time):
for i in range(2):
print("start playing {}.{}".format(file, ctime()))
sleep(time)
list={"a.mp3":3, "b.mp4":5, "c.mp3":4}
threads=[]
files=range(len(list))
for file, time in list.items():
t=threading.Thread(target=super_player, args=(file, time))
threads.append(t)
if __name__ == '__main__':
for i in files:
threads[i].start()
for i in files:
threads[i].join()
print("end:{}".format(ctime()))所显示结果如下：
start playing a.mp3.Tue Dec 4 18:44:25 2018
start playing b.mp4.Tue Dec 4 18:44:25 2018
start playing c.mp3.Tue Dec 4 18:44:25 2018
start playing a.mp3.Tue Dec 4 18:44:28 2018
start playing c.mp3.Tue Dec 4 18:44:29 2018
start playing b.mp4.Tue Dec 4 18:44:30 2018
end:Tue Dec 4 18:44:35 2018创立自己的多线程
import threading
from time import ctime, sleep
class my_thread(threading.Thread):
def __init__(self, func, args, name=' '):
threading.Thread.__init__(self)
self.name=name
self.func=func
self.args=args
def run(self):
self.func(*self.args)
def super_play(file, time):
for i in range(2):
print("start playing {}.{}".format(file, ctime()))
sleep(time)
list = {'a.mp3':3,'b.mp4':5}
threads=[]
files=range(len(list))
for file, time in list.items():
t=my_thread(super_play, (file, time), super_play.__name__)
threads.append(t)
if __name__ == '__main__':
for i in files:
threads[i].start()
for i in files:
threads[i].join()
print("end:{}".format(ctime()))
结果如下：
start playing a.mp3.Tue Dec 4 18:57:00 2018
start playing b.mp4.Tue Dec 4 18:57:00 2018
start playing a.mp3.Tue Dec 4 18:57:03 2018
start playing b.mp4.Tue Dec 4 18:57:05 2018
end:Tue Dec 4 18:57:10 2018