Python “；ValueError：需要多个值才能解包”；多处理

我有以下代码：

def characterize_file(filename):
    try:
        # …
        return (filename, characterization)
    except Exception as e:
        print(filename)
        traceback.print_exc()
        raise e

def write_characterization(args):
    # …
    p = multiprocessing.Pool(3)
    characterizations = p.imap(characterize_file, args)
    for (i, (filename, characterization)) in enumerate(characterizations):
        pass # …

有时，在没有任何其他输出的情况下，我会遇到此异常：

  File "/home/progval/etudes/ens/image/dm/venv/local/lib/python2.7/site-packages/mogulex/main.py", line 52, in write_characterization
    for (i, (filename, characterization)) in enumerate(characterizations):
  File "/usr/lib/python2.7/multiprocessing/pool.py", line 659, in next
    raise value
ValueError: need more than 1 value to unpack

---

它从哪里来？try语句不应该捕获任何错误并打印出来吗？

尝试打印

enumerate（characterizations）

并查看返回了多少值。不过，上次修改后我忘了重新编译代码。该错误实际上来自于try:语句之前调用的某个函数。因此，您应该将其添加为答案。这可能发生在其他人身上。