Python Jumpstart by Building 10 Apps Transcripts
Chapter: App 10: Movie Search App
Lecture: Concept: try except
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Let's close out application ten by looking at this concept of try except blocks.
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Here you can see we have a couple of methods that we are going to call,
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method one, two and three, and they may call other methods,
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and those methods call other methods, down deep into the Python standard library
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and maybe in one of them way down there there is a possibility
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that one throws a connection error.
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Kind of like we saw with our request method calls, when the network was down.
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Now, it doesn't matter how deep down the chain you are or anything like that,
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if there is an exception and it is not handled,
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then it's going to be raised and it will fly up here,
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it will immediately start making its way, if let's say method two has the exception,
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so it will start run method one, successfully,
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method two will run until it hits the exception- done,
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it will skip method three it goes straight to here.
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Now test, is the error a connection error,
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does it derive from or is it exactly this class,
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if that is true then we'll be int his exception block.
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If that's not true, it will keep going down the list.
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Now the order here matters a lot if you say exception at top
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and then connection error at the bottom
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because it just stops and the first one it hits their matches,
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it said you are done for it, it will actually never ever process the connection error
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if you have a more base error or a more generic
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general error handling block at the top,
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super important to go from most specific
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to least specific as you go through this.
