ThreadPoolExecutor未定义[python3]

Question

我正在尝试运行以下代码，这段代码是直接从文档中复制过来的：https://docs.python.org/dev/library/concurrent.futures.html#module-concurrent.futures：

import executor
import concurrent.futures
import time

def wait_on_b():
    time.sleep(5)
    print(b.result()) # b will never complete because it is waiting on a.                                
    return 5

def wait_on_a():
    time.sleep(5)
    print(a.result()) # a will never complete because it is waiting on b.                                
    return 6


executor = ThreadPoolExecutor(max_workers=2)
a = executor.submit(wait_on_b)
b = executor.submit(wait_on_a)

然后我得到了以下输出：

Traceback (most recent call last):
  File "test1.py", line 16, in <module>
    executor = ThreadPoolExecutor(max_workers=2)
NameError: name 'ThreadPoolExecutor' is not defined

我在想可能是我忘记导入某些东西，但我不知道具体是什么。

Answer 1

你可以选择用 from concurrent.futures import ThreadPoolExecutor 来代替 import concurrent.futures，或者保持原来的导入方式，然后使用 executor = concurrent.futures.ThreadPoolExecutor(maxworkers=2)。

另外要注意，你复制的示例代码是故意设计成会死锁的，所以即使你解决了导入的问题，它也不会正常工作。