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 someProprietaryModuleexcept 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: someProprietaryModuleDuring 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 = Truetry:   import someProprietaryModuleexcept ImportError:   _moduleInstalled = Falseif 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:

   import someProprietaryModule

except ImportError:

   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:

    import someProprietaryModule

except ImportError as e:

    raised_error = e

if isinstance(raised_error, ImportError):

    raise ImportError('It appears that <someProprietaryModule> is not installed...')