Using a variable in a try,catch,finally statement without declaring it outside

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执念已碎
执念已碎 2020-12-25 11:07

I\'m pretty new to Python, here is some code I am looking at:

try:
    connection = getConnection(database)
    cursor = connection.cursor()
    cursor.execu         


        
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  • 2020-12-25 11:57

    Python does not have block scope. Anything defined inside the try block will be available outside.

    That said, you would still have a problem: if it is the getConnection() call that raises the error, cursor will be undefined, so the reference in the finally block will error.

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  • 2020-12-25 12:06

    I'd suggest using contexts, like:

    from contextlib import closing
    
    try:
        with closing(getConnection(database)) as connection:
            with closing(connection.cursor()) as cursor:
                cursor.execute("some query")
    except:
        log.error("Problem")
        raise
    

    This should ensure the closing (see more here). In some cases, you won't even need closing since connection is most likely to support the context protocol itself, so that would be just with getConnection(database)...

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