python线程的几种创建方式详解

import threadingfrom time import sleep,ctimedef sing():  for i in range(3):    print("正在唱歌...%d"%i)    sleep(1)def dance():  for i in range(3):    print("正在跳舞...%d"%i)    sleep(1)if __name__ == '__main__':  print('---开始---:%s'%ctime())  t1 = threading.Thread(target=sing)  t2 = threading.Thread(target=dance)  t1.start()  t2.start()  #sleep(5) # 屏蔽此行代码，试试看，程序是否会立马结束？  print('---结束---:%s'%ctime())"""输出结果：---开始---:Sat Aug 24 08:44:21 2019正在唱歌...0正在跳舞...0---结束---:Sat Aug 24 08:44:21 2019正在唱歌...1正在跳舞...1正在唱歌...2正在跳舞...2"""

import threadingimport timeclass MyThread(threading.Thread):  def run(self):    for i in range(3):      time.sleep(1)      msg = "I'm "+self.name+' @ '+str(i) #name属性中保存的是当前线程的名字      print(msg)if __name__ == '__main__':  t = MyThread()  t.start()"""输出结果：I'm Thread-5 @ 0I'm Thread-5 @ 1I'm Thread-5 @ 2"""

from concurrent.futures import ThreadPoolExecutorimport timeimport osdef sayhello(a):  for i in range(10):    time.sleep(1)    print("hello: " + a)def main():  seed = ["a", "b", "c"]  # 最大线程数为3，使用with可以自动关闭线程池，简化操作  with ThreadPoolExecutor(3) as executor:    for each in seed:       # map可以保证输出的顺序, submit输出的顺序是乱的      executor.submit(sayhello, each)  print("主线程结束")if __name__ == '__main__':  main()