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You can cause the flow of the loop to change from inside, by breaking and continuing.
Okay, so branching statements.
0:00
We talked very briefly about break,
Ken you talked about
0:02
maybe you're going down the wall and
you go woo, this milk's bad now.
0:05
You want to break,
you want to just get out of this loop.
0:07
Get me out of here, I don't want to drink
sour milk, the rest of these are all bad.
0:09
You can break out of the loop.
0:12
It's a keyword.
0:13
If you're inside of the loop and
you say break, it will stop going.
0:14
Continue, we'll look at here in a second,
but
0:18
what it does is as you're going through
each one of the lines of the code there.
0:20
If you want to not run the rest of
the lines below, you can call continue and
0:24
it will jump back to the top and
run through again.
0:27
Labels are a thing.
0:30
You can be inside of a loop and
say break, and
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somehow they avoided the words saying
go to, but you can go to a label.
0:36
And through the history of programming,
go to is a bad thing.
0:40
It creates what is known
as spaghetti code.
0:43
Which means that you
try to follow code and
0:45
it looks like little strands of spaghetti.
0:47
And it's not a good thing.
0:50
You can solve a lot without using a label.
0:51
So I say use them sparingly,
they're not common.
0:54
And if you get into a situation where
you want to use one, check yourself.
0:56
[LAUGH]
You don't want to
1:00
introduce spaghetti code.
1:03
You don't want somebody looking at your
code, trying to be like, I went up here.
1:04
Am I over here, where?
1:07
You don't want that.
1:08
But they do exist, and you might see them.
1:09
And you can also return.
1:11
If you're inside of a loop, and
there's something that you're, like, oh,
1:12
this method's done.
1:14
I don't need to do this
thing at all anymore.
1:15
This whole method [INAUDIBLE].
1:16
You can just call a return method there,
and the loop will stop and
1:17
jump out, pop out.
1:20
Okay, so the last example that we
have is the t-shirt give away.
1:21
So, while there's prizes left,
we're gonna ask Is the attendee present?
1:24
If they're not here,
we're gonna try again.
1:29
And let's try again here,
can anybody think of what that is?
1:32
What's this try again?
1:34
We're gonna jump back up to the while.
1:35
There we go, continue, excellent.
1:38
So we're going to continue,
we're going to come back up and
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say is the attendant present?
1:43
If they are here,
we're gonna ask what size.
1:44
And the reason why we
don't want to continue,
1:45
we don't want to ask what
size if they're not here.
1:47
There's no point to do this
extra work that's down here,
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we're not gonna give away
a shirt to nobody either.
1:51
So we have to do that.
1:53
So what I did was I wrote some JavaScript
that [INAUDIBLE] the meetup attendees.
1:53
And not 90 people are here, so
we might have a continue problem.
1:59
We might need to check a continue, but
2:02
I am going to randomly sort that list and
give out some t-shirts.
2:04
That sound good?
2:08
All right, you get a shirt,
you get a shirt.
2:09
>> [LAUGH]
>> All right, so
2:11
the t-shirt code is in here,
called prizes.
2:15
Let's bring this down.
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So I have a list that you don't need
to see, that returns a shuffled
2:22
list of all of the Rsvps.shuffled
at the time that we run this code.
2:26
And I am gonna keep track of
the prizes that are given away,
2:29
and I am also gonna keep
track of the drawingNumber.
2:32
And while we've given away five,
2:36
we are going to pull out of
the RSVP list that number.
2:40
This is that for loop.
2:45
We could have written this with a for
loop, but
2:46
notice that I'm using this drawing number.
2:49
We're gonna say, Is the person present?
2:51
If they're here and
I have to remember to type no.
2:54
Then we're gonna continue.
3:00
So we're calling the continue keyword.
3:04
It's gonna go back up to the top.
3:05
It's not gonna run the rest of this.
3:06
And then we're gonna
ask what size you are.
3:08
You can kinda imagine multiple
bits of this continue or
3:11
multiple bits of this break.
3:14
This isn't working and there's a break.
3:15
Let's imagine that we went past 30 people
and nobody's here, we would call break.
3:18
We can put in different
sorts of things in here.
3:24
You could have a continue in here,
you could have a break in here,
3:25
that sort of thing.
3:27
Then we'll do the prizes given away.
3:31
So I'm gonna assume that you
publicly joined a meetup,
3:32
and your name's on the page already.
3:38
Your name might be in Treehouse Video,
maybe.
3:40
So you kind of win two prizes,
you win a shirt and Treehouse and
3:43
you'll be bummed out if you weren't here,
cuz your name's gonna be in a video.
3:45
>> And you don't have a shirt.
3:48
>> If your name's in the video and
you see this at home and you weren't here,
3:50
I'll send you a shirt, okay.
3:54
>> [LAUGH]
>> You're gonna get so busted.
3:55
All right, [LAUGH] all right.
3:59
Her we go.
4:03
Winners, look at winners.
4:04
Is Eric Ewer's present?
4:08
No Eric Ewers.
4:11
So, here we go.
4:12
I'm gonna say no and it's gonna continue.
4:14
Summer present?
4:19
Yeah, all right.
4:20
>> [APPLAUSE]
>> So I'm gonna say anything.
4:22
I'm gonna say, yep, Summer's here,
and what's your t-shirt size?
4:24
>> Small.
4:29
>> Small, okay.
4:30
Path's posse, path post.
4:31
>> Yeah, that's me.
4:36
>> That's you?
4:37
Yeah, all right, so
we'll loop here till we hit five.
4:38
All right.
4:43
I'm not actually gonna
use this data we're just,
4:48
I was kind of trying to
show that we did the.
4:50
Sarah I know her, and
she is not here, Sarah.
4:52
>> [LAUGH]
>> Is Amy present?
4:57
All right.
4:59
>> [APPLAUSE]
>> Ashley.
5:00
>> [APPLAUSE]
>> All right,
5:07
Simone Flore?
5:12
No, Simone.
5:16
>> [LAUGH]
>> Yeah.
5:17
>> [APPLAUSE]
>> There we go.
5:20
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