# 方法一 
import threading
import time
def func(id):  
    print('threading:%s' % id)
    time.sleep(2)
    print('%s done...' % id)
t1 = threading.Thread(target=func,args=(1,))  #创建线程对象  
t2 = threading.Thread(target=func,args=(2,))
t1.start()   #启动线程
t2.start()

#方法二
import threading
import time
class my_thread(threading.Thread):
    def __init__(self,name,id):
        super(my_thread, self).__init__()
        self.name = name
        self.id = id
    def run(self):   # 必须命名一个run()方法，线程对象调用start()方法时会执行run()的内容
        print('thread id:%s, name:%s' % (self.name,self.id))
        time.sleep(2)
t1 = my_thread('t1',1)
t2 = my_thread('t2',2)
t1.start()
t2.start()

import threading,time

class my_thread(threading.Thread):
    def __init__(self,num):
        super(my_thread,self).__init__()
        self.num = num
    def run(self):
        print('Thread:',self.num)
        # print('thread info:',threading.current_thread())
        time.sleep(2)
        
thread_obj_list = []
for i in range(50):
    t = my_thread(i)
    thread_obj_list.append(t)
    t.start()
    
print('active threads:',threading.active_count())
for t in thread_obj_list:
    t.join()
print('active threads:',threading.active_count())

print('main program exit...')