Question

我试图运行以下代码，该代码直接从文档中复制：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)

我得到以下输出：

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

我假设我忘了导入某些东西，但我不知道。

Answer 1

使用from concurrent.futures import ThreadPoolExecutor代替import concurrent.futures，或按原样保留导入并使用executor = concurrent.futures.ThreadPoolExecutor(maxworkers=2)。

另请注意，您复制的示例代码旨在实现死锁，因此一旦修复导入问题，它就无法正常工作。

ThreadPoolExecutor未定义[python3]

1 个答案: