Python多线程循环

Posted 2020-08-27

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背景：Python脚本：读取文件中每行，放入列表中；循环读取列表中的每个元素，并做处理操作。

核心：多线程处理单个for循环函数调用

模块：threading

第一部分：

：多线程脚本 (该脚本只有两个线程，t1循环次数<t2)

#!/usr/bin/env python
#-*- coding: utf8 -*-

import sys
import time
import string
import threading
import datetime
fileinfo = sys.argv[1]

# 读取文件内容放入列表
host_list = []
port_list = []
 
# 定义函数：读取文件内容放入列表中
def CreateList():
    f = file(fileinfo,‘r‘)
    for line in f.readlines():
        host_list.append(line.split(‘ ‘)[0])
        port_list.append(line.split(‘ ‘)[1])
    return host_list
    return port_list
    f.close()
 
# 单线程 循环函数，注释掉了
#def CreateInfo():    
#    for i in range(0,len(host_list)):     # 单线程：直接循环列表
#        time.sleep(1)
#        TimeMark = datetime.datetime.now().strftime(‘%Y-%m-%d %H:%M:%S‘)
#        print "The Server‘s HostName is %-15s and Port is %-4d !!! [%s]" % (host_list[i],int(port_list[i]),TimeMark)
#    
 
#  定义多线程循环调用函数 
def MainRange(start,stop):     #提供列表index起始位置参数
    for i in range(start,stop):
        time.sleep(1)
        TimeMark = datetime.datetime.now().strftime(‘%Y-%m-%d %H:%M:%S‘)
        print "The Server‘s HostName is %-15s and Port is %-4d !!! [%s]" % (host_list[i],int(port_list[i]),TimeMark)
 
# 执行函数，生成列表
CreateList()
# 列表分割成：两部分 mid为列表的index中间位置
mid = int(len(host_list)/2)
 
# 多线程部分
threads = []
t1 = threading.Thread(target=MainRange,args=(0,mid))
threads.append(t1)
t2 = threading.Thread(target=MainRange,args=(mid,len(host_list)))
threads.append(t2)

for t in threads:
    t.setDaemon(True)
    t.start()
t.join()
print "ok"

以上是脚本内容！！！

----------------------------------------------------------------------

：读取文件的内容

文件内容：

[[email protected] logdb]# cat hostinfo.txt
192.168.10.11 1011
192.168.10.12 1012
192.168.10.13 1013
192.168.10.14 1014
192.168.10.15 1015
192.168.10.16 1016
192.168.10.17 1017
192.168.10.18 1018
192.168.10.19 1019
192.168.10.20 1020
192.168.10.21 1021
192.168.10.22 1022
192.168.10.23 1023
192.168.10.24 1024
192.168.10.25 1025

：输出结果：

单线程 : 执行脚本：输出结果：

[[email protected] logdb]# ./Threadfor.py hostinfo.txt
The Server‘s HostName is 192.168.10.10   and Port is 1010 !!! [2017-01-10 14:25:14]
The Server‘s HostName is 192.168.10.11   and Port is 1011 !!! [2017-01-10 14:25:15]
The Server‘s HostName is 192.168.10.12   and Port is 1012 !!! [2017-01-10 14:25:16]
     .

.
The Server‘s HostName is 192.168.10.25 and Port is 1025 !!! [2017-01-10 14:25:29]

多线程：执行脚本：输出结果

[[email protected] logdb]# ./Threadfor.py hostinfo.txt
The Server‘s HostName is 192.168.10.11 and Port is 1011 !!! [2017-01-10 14:51:51]
The Server‘s HostName is 192.168.10.18 and Port is 1018 !!! [2017-01-10 14:51:51]
The Server‘s HostName is 192.168.10.12 and Port is 1012 !!! [2017-01-10 14:51:52]
The Server‘s HostName is 192.168.10.19 and Port is 1019 !!! [2017-01-10 14:51:52]
The Server‘s HostName is 192.168.10.13 and Port is 1013 !!! [2017-01-10 14:51:53]
The Server‘s HostName is 192.168.10.20 and Port is 1020 !!! [2017-01-10 14:51:53]
The Server‘s HostName is 192.168.10.14 and Port is 1014 !!! [2017-01-10 14:51:54]
The Server‘s HostName is 192.168.10.21 and Port is 1021 !!! [2017-01-10 14:51:54]
The Server‘s HostName is 192.168.10.15 and Port is 1015 !!! [2017-01-10 14:51:55]
The Server‘s HostName is 192.168.10.22 and Port is 1022 !!! [2017-01-10 14:51:55]
The Server‘s HostName is 192.168.10.16 and Port is 1016 !!! [2017-01-10 14:51:56]
The Server‘s HostName is 192.168.10.23 and Port is 1023 !!! [2017-01-10 14:51:56]
The Server‘s HostName is 192.168.10.17 and Port is 1017 !!! [2017-01-10 14:51:57]
The Server‘s HostName is 192.168.10.24 and Port is 1024 !!! [2017-01-10 14:51:57]
The Server‘s HostName is 192.168.10.25 and Port is 1025 !!! [2017-01-10 14:51:58]

==================================以上部分完结===正确=========

=====经过调试出现新的问题======================================

第二部分：延伸问题

总结：以上运行结果没有问题！！！（但是调整参数：start，stop之后有问题：MainRange(start,stop)）

首先说明下两个概念问题：

　　join()：

　　　　1.方法的位置是在for循环外的，也就是说必须等待for循环里的两个进程都结束后，才去执行主进程（主进程指：本脚本中的print “OK”）。

　　　　2.可以理解成：t.join() 的t线程执行完之后，再继续执行后面的！！！（本脚本中的t.join()，是指t2线程）

　　　　可参考：

　　　　　　for i in range(0,4):

　　　　　　　　pass

　　　　　　print i

　　　　　　结果输出：3. 也就是for循环的最后一个i. 放在本脚本里，就是for循环的最后一个线程t2。然后t2完成之后，就是：print “OK”

　　setDaemon(True):

　　　　1.将线程声明为守护线程，必须在start() 方法调用之前设置，如果不设置为守护线程程序会被无限挂起。

　　　　2.换句话说：开启，子线程不会挂起，主线程执行了，子线程及时没执行完也会中断：比如本脚本里如果：t1>t2

===========解析=============================================================

重新编写输出文件内容：

[[email protected] logdb]# cat hostinfo.txt
192.168.10.00 0
192.168.10.01 1
192.168.10.02 2
192.168.10.03 3
192.168.10.04 4
192.168.10.05 5
192.168.10.06 6
192.168.10.07 7
192.168.10.08 8
192.168.10.09 9
192.168.10.10 10
192.168.10.11 11
192.168.10.12 12
192.168.10.13 13
192.168.10.14 14

原文脚本中：

for t in threads:
    t.setDaemon(True)
    t.start()
t.join()
print "ok" 

分类解析：

基于原文脚本：

1. 以上基于线程执行次数：t1 <= t2　　运行结果：正确

[[email protected] logdb]# ./Threadfor.py hostinfo.txt
The Server‘s HostName is 192.168.10.00   and Port is 00 !!! [2017-01-10 19:08:44],
The Server‘s HostName is 192.168.10.07   and Port is 07 !!! [2017-01-10 19:08:44],
The Server‘s HostName is 192.168.10.01   and Port is 01 !!! [2017-01-10 19:08:45],
The Server‘s HostName is 192.168.10.08   and Port is 08 !!! [2017-01-10 19:08:45],
The Server‘s HostName is 192.168.10.02   and Port is 02 !!! [2017-01-10 19:08:46],
The Server‘s HostName is 192.168.10.09   and Port is 09 !!! [2017-01-10 19:08:46],
The Server‘s HostName is 192.168.10.03   and Port is 03 !!! [2017-01-10 19:08:47],
The Server‘s HostName is 192.168.10.10   and Port is 10 !!! [2017-01-10 19:08:47],
The Server‘s HostName is 192.168.10.04   and Port is 04 !!! [2017-01-10 19:08:48],
The Server‘s HostName is 192.168.10.11   and Port is 11 !!! [2017-01-10 19:08:48],
The Server‘s HostName is 192.168.10.05   and Port is 05 !!! [2017-01-10 19:08:49],
The Server‘s HostName is 192.168.10.12   and Port is 12 !!! [2017-01-10 19:08:49],
The Server‘s HostName is 192.168.10.06   and Port is 06 !!! [2017-01-10 19:08:50],
The Server‘s HostName is 192.168.10.13   and Port is 13 !!! [2017-01-10 19:08:50],
The Server‘s HostName is 192.168.10.14   and Port is 14 !!! [2017-01-10 19:08:51],
ok

　　解析：开启setDaemon(True)，t1,t2同时依次执行，[t1,t2],[t1,t2],[t1,t2],[t1,t2],[t1,t2] . . . . . .[t1,t2], 下次循环t1结束，t2再执行一次，[,t2]，再下次，t2结束。t.join()==t2.join() 完成任务，继续执行主进程print “ok”

2.基于脚本中线程次数t1>t2，运行结果：错误

[[email protected] logdb]# ./Threadfor.py hostinfo.txt
t1: (0~13)
t2: (7~15)
The Server‘s HostName is 192.168.10.00   and Port is 00 !!! [2017-01-10 19:18:58],
The Server‘s HostName is 192.168.10.07   and Port is 07 !!! [2017-01-10 19:18:58],
The Server‘s HostName is 192.168.10.01   and Port is 01 !!! [2017-01-10 19:18:59],
The Server‘s HostName is 192.168.10.08   and Port is 08 !!! [2017-01-10 19:18:59],
The Server‘s HostName is 192.168.10.02   and Port is 02 !!! [2017-01-10 19:19:00],
The Server‘s HostName is 192.168.10.09   and Port is 09 !!! [2017-01-10 19:19:00],
The Server‘s HostName is 192.168.10.03   and Port is 03 !!! [2017-01-10 19:19:01],
The Server‘s HostName is 192.168.10.10   and Port is 10 !!! [2017-01-10 19:19:01],
The Server‘s HostName is 192.168.10.04   and Port is 04 !!! [2017-01-10 19:19:02],
The Server‘s HostName is 192.168.10.11   and Port is 11 !!! [2017-01-10 19:19:02],
The Server‘s HostName is 192.168.10.12   and Port is 12 !!! [2017-01-10 19:19:03],
The Server‘s HostName is 192.168.10.05   and Port is 05 !!! [2017-01-10 19:19:03],
The Server‘s HostName is 192.168.10.13   and Port is 13 !!! [2017-01-10 19:19:04],
The Server‘s HostName is 192.168.10.06   and Port is 06 !!! [2017-01-10 19:19:04],
The Server‘s HostName is 192.168.10.07   and Port is 07 !!! [2017-01-10 19:19:05],
The Server‘s HostName is 192.168.10.14   and Port is 14 !!! [2017-01-10 19:19:05],
ok

　　解析：t1,t2同时依次执行，t1>t2，当t2执行最后一次时，t.join()===t2.join()，t.join()完成任务，执行主程序print "ok"，由于：开启setDaemon(True)，t1,t2均不会被挂起，主程序结束，子程序即使没有执行完，也结束。如上述结果。

　　t2执行8次结束，t1也执行8次循环结束。

开启：t.setDaemon(True)：不会挂起，顺序执行

1.脚本如下：

for t in threads:

　　t.setDaemon(True)

　　t.start()

　　t.join() 　　#在for循环里面

print "ok"

[[email protected] logdb]# ./Threadfor.py hostinfo.txt
t1: (0~13)
t2: (7~15)
The Server‘s HostName is 192.168.10.00   and Port is 00 !!! [2017-01-10 19:30:56]
The Server‘s HostName is 192.168.10.01   and Port is 01 !!! [2017-01-10 19:30:57]
The Server‘s HostName is 192.168.10.02   and Port is 02 !!! [2017-01-10 19:30:58]
The Server‘s HostName is 192.168.10.03   and Port is 03 !!! [2017-01-10 19:30:59]
The Server‘s HostName is 192.168.10.04   and Port is 04 !!! [2017-01-10 19:31:00]
The Server‘s HostName is 192.168.10.05   and Port is 05 !!! [2017-01-10 19:31:01]
The Server‘s HostName is 192.168.10.06   and Port is 06 !!! [2017-01-10 19:31:02]
The Server‘s HostName is 192.168.10.07   and Port is 07 !!! [2017-01-10 19:31:03]
The Server‘s HostName is 192.168.10.08   and Port is 08 !!! [2017-01-10 19:31:04]
The Server‘s HostName is 192.168.10.09   and Port is 09 !!! [2017-01-10 19:31:05]
The Server‘s HostName is 192.168.10.10   and Port is 10 !!! [2017-01-10 19:31:06]
The Server‘s HostName is 192.168.10.11   and Port is 11 !!! [2017-01-10 19:31:07]
The Server‘s HostName is 192.168.10.12   and Port is 12 !!! [2017-01-10 19:31:08]
The Server‘s HostName is 192.168.10.07   and Port is 07 !!! [2017-01-10 19:31:09]
The Server‘s HostName is 192.168.10.08   and Port is 08 !!! [2017-01-10 19:31:10]
The Server‘s HostName is 192.168.10.09   and Port is 09 !!! [2017-01-10 19:31:11]
The Server‘s HostName is 192.168.10.10   and Port is 10 !!! [2017-01-10 19:31:12]
The Server‘s HostName is 192.168.10.11   and Port is 11 !!! [2017-01-10 19:31:13]
The Server‘s HostName is 192.168.10.12   and Port is 12 !!! [2017-01-10 19:31:14]
The Server‘s HostName is 192.168.10.13   and Port is 13 !!! [2017-01-10 19:31:15]
The Server‘s HostName is 192.168.10.14   and Port is 14 !!! [2017-01-10 19:31:16]
ok

　　：解析：t.join()在for循环里面，t1.join()等待t1执行13次循环完毕;然后才执行t2,t2.join()等待t2循环执行8次；然后执行主线程print"ok"

　　 :如上述结果：t1先执行完，再执行t2

　　：t1,t2大小无所谓，多线程没有效果

关闭：t.setDaemon(True) :线程会挂起

1.脚本如下：

for t in threads:

#　　t.setDaemon(True)

　　t.start()

　　t.join() 　　#在for循环里面

print "ok"

[[email protected] logdb]# ./Threadfor.py hostinfo.txt
t1: (0~13)
t2: (7~15)
The Server‘s HostName is 192.168.10.00   and Port is 00 !!! [2017-01-10 19:37:11]
The Server‘s HostName is 192.168.10.01   and Port is 01 !!! [2017-01-10 19:37:12]
The Server‘s HostName is 192.168.10.02   and Port is 02 !!! [2017-01-10 19:37:13]
The Server‘s HostName is 192.168.10.03   and Port is 03 !!! [2017-01-10 19:37:14]
The Server‘s HostName is 192.168.10.04   and Port is 04 !!! [2017-01-10 19:37:15]
The Server‘s HostName is 192.168.10.05   and Port is 05 !!! [2017-01-10 19:37:16]
The Server‘s HostName is 192.168.10.06   and Port is 06 !!! [2017-01-10 19:37:17]
The Server‘s HostName is 192.168.10.07   and Port is 07 !!! [2017-01-10 19:37:18]
The Server‘s HostName is 192.168.10.08   and Port is 08 !!! [2017-01-10 19:37:19]
The Server‘s HostName is 192.168.10.09   and Port is 09 !!! [2017-01-10 19:37:20]
The Server‘s HostName is 192.168.10.10   and Port is 10 !!! [2017-01-10 19:37:21]
The Server‘s HostName is 192.168.10.11   and Port is 11 !!! [2017-01-10 19:37:22]
The Server‘s HostName is 192.168.10.12   and Port is 12 !!! [2017-01-10 19:37:23]
The Server‘s HostName is 192.168.10.07   and Port is 07 !!! [2017-01-10 19:37:24]
The Server‘s HostName is 192.168.10.08   and Port is 08 !!! [2017-01-10 19:37:25]
The Server‘s HostName is 192.168.10.09   and Port is 09 !!! [2017-01-10 19:37:26]
The Server‘s HostName is 192.168.10.10   and Port is 10 !!! [2017-01-10 19:37:27]
The Server‘s HostName is 192.168.10.11   and Port is 11 !!! [2017-01-10 19:37:28]
The Server‘s HostName is 192.168.10.12   and Port is 12 !!! [2017-01-10 19:37:29]
The Server‘s HostName is 192.168.10.13   and Port is 13 !!! [2017-01-10 19:37:30]
The Server‘s HostName is 192.168.10.14   and Port is 14 !!! [2017-01-10 19:37:31]
ok

　　解析：由于t.join()在循环里面，所以：t1线程执行完，才执行t2.是顺序执行的

　　t1,t2大小无所谓，多线程没有效果

2.脚本如下：

for t in threads:

#　　t.setDaemon(True)

　　t.start()

t.join() 　　#在for循环外面

print "ok"

[[email protected] logdb]# ./Threadfor.py hostinfo.txt
t1: (0~13)
t2: (7~15)
The Server‘s HostName is 192.168.10.00   and Port is 00 !!! [2017-01-10 19:40:31]
The Server‘s HostName is 192.168.10.07   and Port is 07 !!! [2017-01-10 19:40:31]
The Server‘s HostName is 192.168.10.01   and Port is 01 !!! [2017-01-10 19:40:32]
The Server‘s HostName is 192.168.10.08   and Port is 08 !!! [2017-01-10 19:40:32]
The Server‘s HostName is 192.168.10.02   and Port is 02 !!! [2017-01-10 19:40:33]
The Server‘s HostName is 192.168.10.09   and Port is 09 !!! [2017-01-10 19:40:33]
The Server‘s HostName is 192.168.10.03   and Port is 03 !!! [2017-01-10 19:40:34]
The Server‘s HostName is 192.168.10.10   and Port is 10 !!! [2017-01-10 19:40:34]
The Server‘s HostName is 192.168.10.04   and Port is 04 !!! [2017-01-10 19:40:35]
The Server‘s HostName is 192.168.10.11   and Port is 11 !!! [2017-01-10 19:40:35]
The Server‘s HostName is 192.168.10.05   and Port is 05 !!! [2017-01-10 19:40:36]
The Server‘s HostName is 192.168.10.12   and Port is 12 !!! [2017-01-10 19:40:36]
The Server‘s HostName is 192.168.10.06   and Port is 06 !!! [2017-01-10 19:40:37]
The Server‘s HostName is 192.168.10.13   and Port is 13 !!! [2017-01-10 19:40:37]
The Server‘s HostName is 192.168.10.07   and Port is 07 !!! [2017-01-10 19:40:38]
The Server‘s HostName is 192.168.10.14   and Port is 14 !!! [2017-01-10 19:40:38]
ok
The Server‘s HostName is 192.168.10.08   and Port is 08 !!! [2017-01-10 19:40:39]
The Server‘s HostName is 192.168.10.09   and Port is 09 !!! [2017-01-10 19:40:40]
The Server‘s HostName is 192.168.10.10   and Port is 10 !!! [2017-01-10 19:40:41]
The Server‘s HostName is 192.168.10.11   and Port is 11 !!! [2017-01-10 19:40:42]
The Server‘s HostName is 192.168.10.12   and Port is 12 !!! [2017-01-10 19:40:43]

　　解析：t.join()在循环外面t.join()==t2.join(),

　　过程：t1>t2. 开始：同时执行。当t2执行8次循环完毕，t1也执行了8次。此时t2完毕，t.join()生效，会执行主进程print "ok". 主进程完毕。

　　　　由于，关闭：t.setDaemon(True)，未执行完毕的t1先前被挂起，接下来会继续，直到结束。如上述结果

　　t1<t2 就不会出现这种情况了。多线程是有效的。但是主线程的输出位置，错误！！

！

=============解决方法================================

解决方式：

1.只有两个线程时

修改原脚本：临时解决t1>t2

for t in threads:

　　t.setDaemon(True)

　t.start()　　

threads[0].join() 　　#指定t1,结束

print "ok"

　　解析：通过threads[0] 指定t1.join() ，等t1完成了，才执行主程序

2.多个线程时也适用

for t in threads:

　　t.start()

for t in threads:

　　t.join()

print "ok"

　　解析：多个线程都等待，等所有都完成之后。才执行主线程print "ok"

3.事例：3个线程

[[email protected] logdb]# ./Threadfor.py hostinfo.txt
t1: (0~4)　　循环4次
t2: (4~11)　循环7次

t3: (11~15) 循环4次
The Server‘s HostName is 192.168.10.00   and Port is 00 !!! [2017-01-10 20:07:31]
The Server‘s HostName is 192.168.10.04   and Port is 04 !!! [2017-01-10 20:07:31]
The Server‘s HostName is 192.168.10.11   and Port is 11 !!! [2017-01-10 20:07:31] 　　1次
The Server‘s HostName is 192.168.10.01   and Port is 01 !!! [2017-01-10 20:07:32]
The Server‘s HostName is 192.168.10.05   and Port is 05 !!! [2017-01-10 20:07:32]
The Server‘s HostName is 192.168.10.12   and Port is 12 !!! [2017-01-10 20:07:32]　　2次
The Server‘s HostName is 192.168.10.02   and Port is 02 !!! [2017-01-10 20:07:33]
The Server‘s HostName is 192.168.10.06   and Port is 06 !!! [2017-01-10 20:07:33]
The Server‘s HostName is 192.168.10.13   and Port is 13 !!! [2017-01-10 20:07:33]　　3次
The Server‘s HostName is 192.168.10.03   and Port is 03 !!! [2017-01-10 20:07:34]
The Server‘s HostName is 192.168.10.07   and Port is 07 !!! [2017-01-10 20:07:34]
The Server‘s HostName is 192.168.10.14   and Port is 14 !!! [2017-01-10 20:07:34]　　4次
The Server‘s HostName is 192.168.10.08   and Port is 08 !!! [2017-01-10 20:07:35]　　5次
The Server‘s HostName is 192.168.10.09   and Port is 09 !!! [2017-01-10 20:07:36]　　6次
The Server‘s HostName is 192.168.10.10   and Port is 10 !!! [2017-01-10 20:07:37]　　7次
ok

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