如何修改一行Python代码实现ThreadPoolExecutor线程编号打印

现有一段使用concurrent.futures.ThreadPoolExecutor的Python代码，当前执行后输出如下：

MainThread done at sec 1
MainThread done at sec 1
MainThread done at sec 2
MainThread done at sec 1
MainThread done at sec 0
MainThread done at sec 3
MainThread done at sec 2
MainThread done at sec 5
MainThread done at sec 4

需要修改为带线程编号的输出，示例如下：

MainThread 1 done at sec 1
MainThread 3 done at sec 1
MainThread 2 done at sec 2
MainThread 3 done at sec 1
MainThread 1 done at sec 0
MainThread 2 done at sec 3
MainThread 2 done at sec 2
MainThread 3 done at sec 5
MainThread 1 done at sec 4

要求仅修改以下代码行实现需求：

print(threading.current_thread().name + ' done at sec ' + str(future.result()))

完整代码如下：

import concurrent.futures
import threading
import pdb
import time
import random


def Threads2(time_sleep):
    time.sleep(time_sleep)
    return time_sleep


all_sections = [random.randint(0, 5) for iii in range(10)]

test1 = []
with concurrent.futures.ThreadPoolExecutor(max_workers=3, thread_name_prefix="Ok") as executor:
    working_threads = {executor.submit(Threads2, time_sleep): time_sleep for index, time_sleep in enumerate(all_sections)}

    for future in concurrent.futures.as_completed(working_threads):
        print(threading.current_thread().name + ' done at sec ' + str(future.result()))

解决方案 #

当前代码中threading.current_thread().name获取的是执行print语句的主线程名称，而非执行任务的工作线程。要获取执行任务的工作线程编号，可通过Future对象的私有属性_thread获取对应的工作线程，再提取编号：

修改后的代码行如下：

print(f"MainThread {future._thread.name.split('Ok')[1]} done at sec {future.result()}")

说明：

1. future._thread指向执行该任务的工作线程对象；
2. 工作线程名称由thread_name_prefix（此处为"Ok"）加编号组成，通过split('Ok')[1]提取出编号；
3. 使用f-string简化字符串拼接，使代码更清晰。

执行修改后的代码，即可得到符合要求的带线程编号的输出。

内容的提问来源于stack exchange，提问作者Rhys