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[_] Python Question

Matthew Wilkes matt at matthewwilkes.name
Mon Dec 28 11:25:03 GMT 2009

On 2009-12-28, at 1136, jan.grant at bristol.ac.uk wrote:

> I still don't get it, Father Ted. Explain to me again why it's  
> better..?

It's just the Python philosophy, both are correct, but exception is  
the standard.

What you're saying by using an exception is "Append this to the list  
at attributes[value]", then telling it that if that list doesn't exist  
("except KeyError") it should create a new list with the element you  
were going to append as the first element.

The point is, instead of programming all the different cases you can  
think of you programme the default case and what to do if there is a  
problem.  Of course, just catching exceptions can't cover all  
possibilities, sometimes you need to use if statements.

Matt