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“在处理上述异常...期间”（及其上方的线）。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...')

但这感觉有点像骇客。我还能做什么？

Answer 1

在raise ... from None这种情况下，可能会使用Python 3.3及更高版本。try:&nbsp; &nbsp;import someProprietaryModuleexcept ImportError:&nbsp; &nbsp;raise ImportError('It appears that <someProprietaryModule> is not installed...') from None这具有期望的结果。

Answer 2

这可以在Python 2.7和Python 3中完成：try:&nbsp; &nbsp; import someProprietaryModuleexcept ImportError as e:&nbsp; &nbsp; raised_error = eif isinstance(raised_error, ImportError):&nbsp; &nbsp; raise ImportError('It appears that <someProprietaryModule> is not installed...')