Python for Absolute Beginners Transcripts
Chapter: Error handling
Lecture: Introduction to Python's error handling
0:00 Well I hope you're proud of the
0:01 little programs that we created are
0:03 rock paper scissors and tic tac toe
0:05 and all the other things.
0:07 And they're pretty good
0:08 but there's something that we've been overlooking so far.
0:11 And the reason they've been over looking it is
0:12 I've been trying to focus on the core programming concepts.
0:16 But no program is done until it is handling bad user input
0:20 or other types of situations that it didn't expect.
0:23 Here we are now rock paper scissors game
0:25 and we have a new player
0:26 crash bandit, uh-oh.
0:28 Well it says please enter a number
0:30 which one would you like?
0:31 1 through 7, I said, Cool, we'll take 7.
0:33 s-e-v-e-n, enter. Boom!
0:37 Our program exploded, it's done.
0:39 It didn't just report that it couldn't understand seven.
0:42 It said, We've crashed so badly, we cannot continue.
0:46 I can see the process finished with exec code 1.
0:49 That might sound good, 0 is good, non-zero is bad.
0:52 See it says there's a ValueError
0:54 input literal for int, uh we can't, it's invalid
0:57 we can't take the word seven, we need the number 7.
1:01 You know the purpose is to take quote, the num
1:03 the numeral 7
1:04 and turn it to literally the integer seven.
1:07 And it can't take it this way.
1:08 Maybe you would expect it could, but it can't.
1:10 So that's a problem, what we need to do is say
1:13 Hey, we saw that you typed in something wrong
1:15 no worries, we got you, that was invalid
1:18 why don't you try something like
1:19 one through seven as a numeral.
1:21 So that's what were going to focus on in this chapter.
1:24 Were going to keep it pretty short and tight.
1:26 But there are some essential error handling things
1:29 we have not touched on, at all.
1:31 And it's going to allow us to catch these errors
1:34 stop them, figure out what went wrong
1:35 tell the user what the problem was
1:37 and potentially let them keep on going.