Python 核心编程笔记六

Python 2017-08

这里简要记录 Python核心编程 读书笔记 整段代码 可以直接运行

CODE-多线程同步-Threading-Class简单封装-1

# -*- coding:gb18030 -*-
# 线程同步 Threading + 简单类封装
import threading
from time import sleep, ctime
loops = [2, 2]
class ThreadFunc(object):
    def __init__(self, func, args, name=''):
        self.func = func
        self.args = args
        self.name = name
    def __call__(self, *args, **kwargs):
        apply(self.func, self.args)
def loop(nloop, during):
    print 'Lopper ', nloop, 'start at: ', ctime()
    sleep(during)
    print 'Lopper ', nloop, 'stop at: ', ctime()
def main():
    print 'Lopper start at: ', ctime()
    threads = []
    nloops = range(len(loops))
    for i in nloops:
        t = threading.Thread(target=ThreadFunc(loop, (i, loops[i]), loop.__name__))
        threads.append(t)
    for i in nloops:
        threads[i].start()
    for i in nloops:
        threads[i].join()
    print 'Lopper stop at: ', ctime()
if __name__ == '__main__':
    main()

RESULT-多线程同步-Threading-Class简单封装-1

C:\Python27\python.exe H:/workspace/python-hw/hw-7.py
Lopper start at:  Wed Aug 09 18:44:41 2017
Lopper  0 start at:  Wed Aug 09 18:44:41 2017
Lopper  1 start at:  Wed Aug 09 18:44:41 2017
Lopper  1 stop at:  Wed Aug 09 18:44:43 2017
Lopper  0 stop at:  Wed Aug 09 18:44:43 2017
Lopper stop at:  Wed Aug 09 18:44:43 2017
Process finished with exit code 0

CODE-多线程同步-Threading-Class简单封装-2

我们将上面代码中L36-40 合并在一个遍历中，其他不变

for i in nloops:
    threads[i].start()
    threads[i].join()

RESULT-多线程同步-Threading-Class简单封装-2

C:\Python27\python.exe H:/workspace/python-hw/hw-7.py
Lopper start at:  Wed Aug 09 18:46:05 2017
Lopper  0 start at:  Wed Aug 09 18:46:05 2017
Lopper  0 stop at:  Wed Aug 09 18:46:07 2017
Lopper  1 start at:  Wed Aug 09 18:46:07 2017
Lopper  1 stop at:  Wed Aug 09 18:46:09 2017
Lopper stop at:  Wed Aug 09 18:46:09 2017
Process finished with exit code 0

CODE-多线程同步-Threading-Class简单封装-3

接着，我们将第一处代码的L38，做个倒序遍历，其他不变。

for i in reversed(nloops):
    threads[i].join()

RESULT-多线程同步-Threading-Class简单封装-3

Lopper start at:  Wed Aug 09 18:47:31 2017
Lopper  0 start at:  Wed Aug 09 18:47:31 2017
Lopper  1 start at:  Wed Aug 09 18:47:31 2017
Lopper  1 stop at:  Wed Aug 09 18:47:33 2017
Lopper  0 stop at:  Wed Aug 09 18:47:33 2017
Lopper stop at:  Wed Aug 09 18:47:33 2017
Process finished with exit code 0

小结

正序遍历和逆序遍历thread，分别调用join方法，而最后的结果完全相同，原因是：
两个方法都是在主线程调用的 所以根本不会关心哪个子线程先执行完 只要两个子线程都执行完了 在执行主线程 就是正确的结果