标签：active 面向对象 start pre bsp one 循环 images tar
1、多线程模块 import threading
2、用函数写一个多线程例子
import threading,time
def talk(name):
print(name,"is tlaking",threading.current_thread(),threading.active_count())
time.sleep(2)
print("thread done ....",name)
p1 = threading.Thread(target=talk,args = ("alex",))
p2 = threading.Thread(target=talk,args = ("japhi",))
p1.start()
p2.start()
结果是：
alex is tlaking <Thread(Thread-1, started 5680)> 2 japhi is tlaking <Thread(Thread-2, started 4592)> 3 thread done .... alex thread done .... japhi
其中threading.current_thread() 用来打印当前的线程，threading.active_count()打印线程数，结果是一起运行。
3、用面向对象的方式写一个多线程
import threading,time
class Mythread(threading.Thread):
def __init__(self,name):
super(Mythread,self).__init__()
self.name = name
def run(self): #必须是run
print(self.name,"is tlaking")
time.sleep(2)
p3 = Mythread("alex")
p4 = Mythread("japhi")
p3.start()
p4.start()
但是，面向对象的形式中的方法名必须是run
4、join（）方法
join方法是指当前线程执行完才能继续执行下一个线程，代码示例
import threading,time
start_time = time.time()
def talk(name):
print(name,"is tlaking",threading.current_thread(),threading.active_count())
time.sleep(2)
print("thread done ....",name)
p1 = threading.Thread(target=talk,args = ("alex",))
p2 = threading.Thread(target=talk,args = ("japhi",))
p1.start()
p1.join()
p2.start()
print("cost:",time.time() - start_time)
结果是：
先打印：alex is tlaking <Thread(Thread-1, started 3444)> 2 2秒后。。。 打印：thread done .... alex japhi is tlaking <Thread(Thread-2, started 11988)> 2 cost: 2.0001144409179688 2秒后打印：thread done .... japhi
等1线程执行完后才执行线程2
4、以一个循环的例子：
import threading,time
start_time = time.time()
def talk(name):
print(name,"is tlaking",threading.current_thread(),threading.active_count())
time.sleep(2)
print("thread done ....",name)
res = []
for i in range(10):
p1 = threading.Thread(target=talk,args = (i,)) #多线程并发，target是任务，args是参数，参数后面一定要加，
p1.setDaemon(True) # 把当前线程变为守护线程
p1.start()
res.append(p1)
for obj in res:
obj.join()
print("cost:",time.time() - start_time)
计算10个线程都结束后花的时间，结果是cost: 2.0021145343780518
5、守护线程
t.setDaemon(True) 将t这个线程设为守护线程，主线程代码结束后不会等t线程是否结束，直接退出程序
import threading,time
start_time = time.time()
def talk(name):
print(name,"is tlaking",threading.current_thread(),threading.active_count())
time.sleep(2)
print("thread done ....",name)
for i in range(10):
p1 = threading.Thread(target=talk,args = (i,)) #多线程并发，target是任务，args是参数，参数后面一定要加，
p1.setDaemon(True) # 把当前线程变为守护线程
p1.start()
print("cost:",time.time() - start_time)
结果是：
标签：active 面向对象 start pre bsp one 循环 images tar
原文地址：http://www.cnblogs.com/japhi/p/7010806.html
