Python：通过具有多个Excepts的Try / Except块传播异常


Python: Propagate an exception through a Try/Except Block with multiple Excepts

有没有办法将try / except块中的异常从一个传播到另一个除外？

我想捕获一个特定的错误，然后进行一般的错误处理。

"raise"允许异常"冒泡"到外部try / except，但不在try / except块内引发错误。

理想情况应该是这样的：

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import logging

def getList():
    try:
        newList = ["just","some","place","holders"]
        # Maybe from something like: newList = untrustedGetList()

        # Faulty List now throws IndexError
        someitem = newList[100]

        return newList

    except IndexError:
        # For debugging purposes the content of newList should get logged.
        logging.error("IndexError occured with newList containing:
%s",   str(newList))

    except:
        # General errors should be handled and include the IndexError as well!
        logging.error("A general error occured, substituting newList with backup")
        newList = ["We","can","work","with","this","backup"]
        return newList

我遇到的问题是当IndexError被第一个捕获时除外，我的常规错误处理在第二个除了块之外没有应用。

我现在唯一的解决方法是在第一个块中包含一般错误处理代码。 即使我将它包装在它自己的功能块中，它仍然看起来不那么优雅......

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您有两种选择：

  • 不要使用专用的except ..块捕获IndexError。 您始终可以通过捕获BaseException并将异常分配给名称(此处为e)来手动测试常规块中的异常类型：

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    try:
        # ...
    except BaseException as e:
        if isinstance(e, IndexError):
            logging.error("IndexError occured with newList containing:
    %s"    ,   str(newList))

        logging.error("A general error occured, substituting newList with backup")
        newList = ["We","can","work","with","this","backup"]
        return newList

  • 使用嵌套的try..except语句并重新引发：

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    try:
        try:
            # ...
        except IndexError:
            logging.error("IndexError occured with newList containing:
    %s"    ,   str(newList))
            raise
    except:
        logging.error("A general error occured, substituting newList with backup")
        newList = ["We","can","work","with","this","backup"]
        return newList
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