python开发之thread线程基础实例入门

本文实例讲述了python开发之thread线程基础。分享给大家供大家参考，具体如下：

说到线程，我们要知道啥是串行，啥是并行程序

举个例子：

串行程序，就是一个一个的执行程序

    #python threading
    import time
    '''
      每一秒中，输出：this is a demo!
    '''
    def serial():
      '''串行输出'''
      time.sleep(1)
      print('this is a demo!')
    def main():
      for i in range(5):
        serial()
    if __name__ == '__main__':
      main()

运行结果如下：

    >>> 
    this is a demo!
    this is a demo!
    this is a demo!
    this is a demo!
    this is a demo!
    >>>

并行程序，就是很多个程序在同一时间(宏观)一起执行

    #python threading
    import threading
    import time
    '''
      并行执行，输出：Good!Good!Good!Good!Good!
    '''
    def parallel():
      '''并行输出'''
      time.sleep(1)
      print('Good!')
    def main():
      for i in range(5):
        t = threading.Thread(target=parallel)
        t.start()
    if __name__ == '__main__':
      main()

当然我们通过执行程序，可以知道，并行程序要比串行程序执行的要快....

我们也可以获取到当前的线程及个数：

    #python threading
    import threading
    import time
    '''
      并行执行，输出：
      [<Thread(Thread-2, started 3480)>, <Thread(Thread-1, started 660)>,
      <Thread(SockThread, started daemon 2920)>, <Thread(Thread-3, started 916)>,
      <Thread(Thread-4, started 3476)>, <_MainThread(MainThread, started 3964)>,
      <Thread(Thread-5, started 2060)>]
      存在的线程数 ： 7
      Good!Good!Good!Good!Good!
    '''
    def parallel():
      '''并行输出'''
      time.sleep(1)
      print('Good!')
    def main():
      for i in range(5):
        t = threading.Thread(target=parallel)
        t.start()
    if __name__ == '__main__':
      main()
      print(threading.enumerate())
      print('存在的线程数 ： %d'%threading.active_count())

运行结果如下：

    >>> 
    [<Thread(SockThread, started daemon 15424)>, <Thread(Thread-3, started 15840)>, <Thread(Thread-1, started 10884)>, <Thread(Thread-2, started 14512)>, <Thread(Thread-4, started 13204)>, <_MainThread(MainThread, started 12924)>, <Thread(Thread-5, started 15476)>]
    存在的线程数 ： 7
    >>> Good!Good!Good!Good!Good!

希望本文所述对大家Python程序设计有所帮助。