Python for Absolute Beginners Transcripts
Chapter: Error handling
Lecture: Stepping through errors in the debugger
Login or
purchase this course
to watch this video and the rest of the course contents.
0:00
I want to do one more thing to just make sure
0:01
that you're really getting in the feel for how
0:03
the control flow works when we hit these errors.
0:07
I'm going to set a breakpoint, right up here.
0:09
And I'm going to hit the debug button.
0:11
And I'm going to come in here, and we're going to step
0:12
either over or into our code.
0:15
So let's step over this, over this, we don't care
0:18
about the log stuff, we don't care about the header stuff.
0:21
And let's go into this load_rolls here, and first
0:23
I'm going to really quickly break this.
0:26
Let's see what's going to happen.
0:28
Let's hit this first, step into our code.
0:31
And this is fine, this is fine, this is fine.
0:34
We've opened it you can see, opened up to that file.
0:37
A little more info. But this, if we even step
0:40
into this, and go deep down into, into Python itself
0:44
and as we try to work through these steps
0:47
what's going to happen, this is going to hit
0:51
this line and go
0:52
broken! And now it stops, what is this?
0:54
No, nothing. Keep going.
0:56
And it's going to start going down through here.
0:58
And now this one is going to actually match this
1:00
and go in here so, it's not going to be so unexpected.
1:03
But it says we have this error, which we named je
1:06
no not surprising and off it goes.
1:09
And then it just exits and so it
1:10
picked one of those blocks and it went.
1:12
Put this back.
1:15
And let's debug it again.
1:17
This time, let's go through, over step over.
1:20
I'm not going to go until we start playing the game a little.
1:23
We'll go down and do that.
1:25
It wants my name I guess.
1:30
And I'm going to go in, and-whoops console.
1:35
I want to throw seven, now actually
1:37
I wanted to stop down here.
1:39
So I didn't step and do it correctly so
1:41
I have to set the breakpoint down here.
1:43
Which is fine, and get roll, and now my roll is
1:45
now let's say seven correctly.
1:48
So, I'm going to step over, and it's
1:50
going to print out the rolls.
1:51
Let's not do the breakpoint there, and right down to here.
1:54
It asks what our roll is, and it's going to be seven.
1:58
And now we're back here, and it got the word seven numeral.
2:02
It's gong to convert that successfully
2:03
I'm going to say it's fine and just going to return
2:05
it's not going to go into the errors
2:07
but it's good, comes down and it just keeps playing.
2:09
And off it goes.
2:10
I don't know if I won, but I'm going to find out
2:12
let's go down a little bit farther to see if I won.
2:14
I, think I won? Yes I took the round.
2:16
Alright let's go farther.
2:18
And now let me type in some junk, something broken.
2:23
So, broken. This is broken. It's fine.
2:27
It says it's not nothing, so everything's good.
2:29
But we're going to try this, and
2:30
it's going to first say, I'm going to start going up
2:33
till I find the first except, the first try-except block.
2:35
It just happens to be right here
2:37
it could be that main one as well.
2:39
So we're going to come over here and step.
2:41
Not going to work, so it goes straight here.
2:43
Handles the error, returns it up here
2:45
and it doesn't go all the way the main
2:47
but it says alright we dealt with it and
2:49
what we decided to do is return none for roll one
2:52
when something invalid was done.
2:54
So that way, we can trigger this bit of code
2:56
to just make us do it again.
2:58
So as you're exploring this error handling
2:59
be sure to use the debugger and step over and into
3:02
and out of your code to explore the flow of the errors
3:06
as you go through the program.
