exception problem

[Charles Hixson]

On 06/24/2012 11:23 PM, Andrew Berg wrote:
> On 6/25/2012 12:27 AM, Charles Hixson wrote:
>    
>> The documentation section covering the except statement could stand to
>> be a *LOT* clearer.   I read the sections on the except statement and
>> exception handlers several times and couldn't figure out was the "as"
>> argument of the except statement was for.
>>      
> I agree that the tutorial doesn't explain the use of "as" very well, but
> it does cover that a bare except is not normally good to use:
> "The last except clause may omit the exception name(s), to serve as a
> wildcard. Use this with extreme caution, since it is easy to mask a real
> programming error in this way!"
>
>    
>> I still don't really know what
>> "as" means, except that if you use it, and you print out the "target",
>> you'll get some kind of informative message.
>>      
> "as" lets you refer to the exception object that was caught. I find this
> useful mainly for exceptions that have attributes (most built-in
> exceptions don't, but many user-defined exceptions do). A full traceback
> is much more useful for debugging than what a simple print(exc) will give.
> There are a few different ways to get traceback information without
> letting the exception simply propagate and terminate the program. You
> can get some simple information from sys.exc_info() (and you can feed
> the traceback object to a function in the traceback module), or you can
> log it with the logging.exception() function or the exception() method
> of a Logger from the same module. I recommend using logging. However,
> it's generally best to just let any unexpected exceptions propagate
> unless the program absolutely must continue, especially when debugging.
>    
I read that that would happen, but "  print (sys.exc_info()[:2]) " 
didn't even yield a blank line.  It must have executed, because the 
print statement on the line before it executed, and there wasn't a loop 
or a jump (and also execution continued "normally" [the code still has 
bugs] afterward even if the finally isn't included).

-- 
Charles Hixson