使用类型class和as语句

try:#code
except Exception as e:
     m=type(e)
     #m is the class of the exception
     strm=str(m)
     #strm is the string of m

你的问题是:“我如何才能确切地看到someFunction()中发生了什么导致异常发生?”

在我看来，您不是在问如何处理生产代码中不可预见的异常(正如许多答案所假设的那样)，而是在问如何找出在开发过程中导致特定异常的原因。

最简单的方法是使用调试器，该调试器可以在未捕获异常发生的地方停止，最好不要退出，以便您可以检查变量。例如，Eclipse开源IDE中的PyDev可以做到这一点。要在Eclipse中启用该功能，请打开Debug透视图，在Run菜单中选择管理Python异常断点，并在未捕获的异常上检查挂起。

使用类型class和as语句

try:#code
except Exception as e:
     m=type(e)
     #m is the class of the exception
     strm=str(m)
     #strm is the string of m

你通常不应该用try来捕获所有可能的异常:…除非这太宽泛了。只要抓住那些无论出于什么原因都会发生的事情。如果您真的必须这样做，例如，如果您想在调试时了解有关某个问题的更多信息，那么您应该这样做

try:
    ...
except Exception as ex:
    print ex # do whatever you want for debugging.
    raise    # re-raise exception.

大多数答案指向except(…)as(…):语法(正确)，但同时没有人想谈论房间里的大象，而大象是sys.exc_info()函数。 来自sys模块的文档(重点是我的):

This function returns a tuple of three values that give information about the exception that is currently being handled. (…) If no exception is being handled anywhere on the stack, a tuple containing three None values is returned. Otherwise, the values returned are (type, value, traceback). Their meaning is: type gets the type of the exception being handled (a subclass of BaseException); value gets the exception instance (an instance of the exception type); traceback gets a traceback object (see the Reference Manual) which encapsulates the call stack at the point where the exception originally occurred.

我认为sys.exc_info()可以被视为对原始问题“我如何知道发生了什么类型的异常?”的最直接答案。

在Python 2中，以下代码很有用

except Exception, exc:

    # This is how you get the type
    excType = exc.__class__.__name__

    # Here we are printing out information about the Exception
    print 'exception type', excType
    print 'exception msg', str(exc)

    # It's easy to reraise an exception with more information added to it
    msg = 'there was a problem with someFunction'
    raise Exception(msg + 'because of %s: %s' % (excType, exc))