- 创建一个Thread的实例，传给它一个可调用的类对象
在练习18.5的例18.5时，照着例子抄错了，如下：
#!/usr/bin/env python
import threading
from time import ctime,sleep
class ThreadFuc(object):
def __init__(self,func,args,name=''):
self.name=name
self.func=func
self.args=args
def __call__(self):
#apply(self.func,self.args)
self.res=self.func(*self.args)
def loop(nloop,nsec):
print("%s start at %s"%(nloop,ctime()))
sleep(nsec)
print("%s ended at %s"%(nloop,ctime()))
def main():
nsect=[2,4]
threads=[]
nloop=range(len(nsect))
print("thread start at %s"%ctime())
for i in nloop:
t=threading.Thread(target=ThreadFuc(loop,(i,nsect[i]),loop.__name__))
threads.append(t)
for i in nloop:
threads[i].start()
for i in nloop:
threads[i].join()
print("all done at %s"%ctime())
if __name__=='__main__':
main()
第21行应该为nsect[i]，却抄例子写错为loop[i]，结果运行后就报错如下：
Traceback (most recent call last):
File "mtsleep4.py", line 28, in <module>
main()
File "mtsleep4.py", line 20, in main
t=threading.Thread(target=ThreadFuc(loop,(i,loop[i]),loop.__name__))
TypeError: 'function' object is unsubscriptable
即调用loop函数时找不到对应参数所以报错。此句即创建了一个ThreadFuc实例，比如a,此实例是可调用的，即运行a.call()。apply(self.func,self.args)在python1.6及以上版本中又可写为self.res=self.func(*self.args)。换句话说，即此实例执行self.res=loop(nsect[i])。这里loop为global值，如果将loop函数算入此类型的方法中，会报global name 'loop' is not defined。最终的运行结果如下：
thread start at Tue Jul 7 19:03:19 2015 0 start at Tue Jul 7 19:03:19 2015 1 start at Tue Jul 7 19:03:19 2015 0 ended at Tue Jul 7 19:03:21 2015 1 ended at Tue Jul 7 19:03:23 2015 all done at Tue Jul 7 19:03:23 2015
2. 从Thread派生一个类，创建这个类的一个实例myThread.py
#!/usr/bin/env python
import threading
from time import ctime,sleep
class MyThread(threading.Thread):
def __init__(self,func,args,name=''):
threading.Thread.__init__(self)
self.name=name
self.func=func
self.args=args
def run(self):
apply(self.func,self.args)
#self.res=self.func(*self.args)
def loop(nloop,nsec):
print("%s start at %s"%(nloop,ctime()))
sleep(nsec)
print("%s ended at %s"%(nloop,ctime()))
def add(num):
print("This is %s thread"%num)
def main():
nsect=[2,4]
threads=[]
nloop=range(len(nsect))
print("thread start at %s"%ctime())
for i in nloop:
t=MyThread(loop,(i,nsect[i]),loop.__name__)
threads.append(t)
for i in nloop:
threads[i].start()
for i in nloop:
threads[i].join()
print("all done at %s"%ctime())
if __name__=='__main__':
main()
3. 利用步骤2的方式来完成斐波那契，阶乘和累加：
#!/usr/local/env python
from time import ctime,sleep
from myThread import MyThread
def fib(n):
sleep(0.0005)
if (n==0):
return 0
elif n==1:
return 1
else:
return(fib(n-2)+fib(n-1))
def sum(n):
sleep(0.1)
if(n<=2):
return 1
else:
return(sum(n-1)+n)
def mult(n):
sleep(0.0001)
if(n<2):
return 1;
else:
return (n*mult(n-1))
def main():
fiction=[mult,sum,fib]
threads=[]
num=12
nloop=range(len(fiction))
print("*****Single thread******")
for i in nloop:
print("%s thread starts at %s"%(fiction[i].__name__,ctime()))
print(fiction[i](num))
print("%s thread ends at %s"%(fiction[i].__name__,ctime()))
print("*****Multi threads******")
for i in nloop:
t=MyThread(fiction[i],(num,),fiction[i].__name__)
threads.append(t)
for i in nloop:
threads[i].start()
for i in nloop:
threads[i].join()
print(threads[i].getResult())
print("Done!")
if __name__=='__main__':
main() 注意创建线程时，第二个参数是一个序列，而不是一个int值，这是apply函数所要求的。 4. 利用线程来实现生产者消费者：
#!/usr/local/env python
from myThread import MyThread
from Queue import Queue
from time import ctime,sleep
from random import randint
def writeQ(queue):
if not queue.full():
print("starting writer at %s"%ctime())
queue.put("x")
print("producing obj for Q...size now is %s"%queue.qsize())
def writer(queue,num):
sleep(0.1)
if num>0:
for i in range(num):
writeQ(queue)
def readeQ(queue):
if not queue.empty():
print("starting condutor at %s"%queue.get())
print("consumed obj for Q...size now is %s"%queue.qsize())
def reader(queue,num):
sleep(0.6)
if num> 0:
for i in range(num):
readeQ(queue)
def main():
q=Queue(10)
threads=[]
function=[writer,reader]
nloop=range(len(function))
print("***********Start production/conduction**************")
for i in nloop:
t=MyThread(function[i],(q,randint(2,4)),function[i].__name__)
threads.append(t)
for i in nloop:
threads[i].start()
for i in nloop:
threads[i].join()
print("*******************Done***************************")
if __name__=='__main__':
main()