多线程

1、简单例子：

　　

import threading import time def work(n):     time.sleep(2)     print ("threading :",n) time1 = time.time() t1 = threading.Thread(target=work,args=("alex",)) t2 = threading.Thread(target=work,args = ("kaka",)) t1.start() t2.start() time2 = time.time() print (time2 - time1) 2、用类实现：

class MyThread(threading.Thread):     def __init__(self,n):         super(MyThread, self).__init__()         self.n = n     def run(self):         print ("run",self.n) a = MyThread("kaka") b = MyThread("wawa") a.run() b.run() -------------------------------------------------------------- 3、主线程启动子线程，子线程独立运行（由原串行变为并行）；

import threading import time def work(n):     time.sleep(2)     print ("threading :",n) start_time = time.time() for i in range(50):     t = threading.Thread(target=work,args = ("threading %s" % i,))     t.start() cost = time.time()-start_time print ("耗时%s" % cost) 4、join()

import threading import time def work(n):     print ("threading %s is start!" % n)     time.sleep(2)     print ("threading %s is done!:" % n) start_time = time.time() res_list = [] for i in range(50):     t = threading.Thread(target=work,args = ("threading %s" % i,))     t.start()     res_list.append(t) for t in res_list:#join相当于wait的意思；等待所有线程结束后，再往下走;     t.join() cost = time.time()-start_time print ("耗时%s" % cost) 5、