当我提出自己的异常作为响应时，如何更轻松地抑制以前的异常？

Question

考虑

try:
   import someProprietaryModule
except ImportError:
   raise ImportError('It appears that <someProprietaryModule> is not installed...')

运行时，如果未安装someProprietaryModule，则会看到：

(traceback data)
ImportError: unknown module: someProprietaryModule

During handling of the above exception, another exception occurred:

(traceback data)
ImportError: It appears that <someProprietaryModule> is not installed...

也许我不希望出现“在处理以上异常…期间”行（及其上方的行）。我可以这样做：

_moduleInstalled = True
try:
   import someProprietaryModule
except ImportError:
   _moduleInstalled = False
if not _moduleInstalled: 
   raise ImportError('It appears that <someProprietaryModule> is not installed...')

但这感觉有点像黑客。我还能做什么？

Answer 1

在Python 3.3及更高版本中，raise ... from None可能会出现这种情况。

try:
   import someProprietaryModule
except ImportError:
   raise ImportError('It appears that <someProprietaryModule> is not installed...') from None

这具有期望的结果。