当我在响应中提出自己的异常时,如何更容易地抑制先前的异常？

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,则可以看到:

(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......"行(以及它上面的行).我能做到这一点:

_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和更高版本中raise ... from None可能会使用这种情况.

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

这具有期望的结果.