Python for Absolute Beginners Transcripts
Chapter: Error handling
Lecture: Introduction to Python's error handling
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Well I hope you're proud of the
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little programs that we created are
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rock paper scissors and tic tac toe
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and all the other things.
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And they're pretty good
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but there's something that we've been overlooking so far.
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And the reason they've been over looking it is
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I've been trying to focus on the core programming concepts.
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But no program is done until it is handling bad user input
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or other types of situations that it didn't expect.
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Here we are now rock paper scissors game
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and we have a new player
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crash bandit, uh-oh.
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Well it says please enter a number
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which one would you like?
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1 through 7, I said, Cool, we'll take 7.
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s-e-v-e-n, enter. Boom!
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Our program exploded, it's done.
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It didn't just report that it couldn't understand seven.
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It said, We've crashed so badly, we cannot continue.
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I can see the process finished with exec code 1.
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That might sound good, 0 is good, non-zero is bad.
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See it says there's a ValueError
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input literal for int, uh we can't, it's invalid
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we can't take the word seven, we need the number 7.
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You know the purpose is to take quote, the num
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the numeral 7
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and turn it to literally the integer seven.
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And it can't take it this way.
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Maybe you would expect it could, but it can't.
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So that's a problem, what we need to do is say
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Hey, we saw that you typed in something wrong
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no worries, we got you, that was invalid
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why don't you try something like
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one through seven as a numeral.
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So that's what were going to focus on in this chapter.
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Were going to keep it pretty short and tight.
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But there are some essential error handling things
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we have not touched on, at all.
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And it's going to allow us to catch these errors
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stop them, figure out what went wrong
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tell the user what the problem was
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and potentially let them keep on going.
