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Feeling Loopy with Java

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Nesting Loops

2:34 with Craig Dennis

You can put loops inside of other loops to create combinations and cross products.

All right, it's hot out there let's do an ice cream example. 0:00
For those of you watching at home, you probably don't know about this place, but 0:04
there is a place here in Portland that likes to make weird ice cream flavors, and 0:07
it mixes sweet and savory, and it's a good combination and so 0:10
I thought this might be a good time. 0:14
It's hot outside, it's really hot today, so let's go make some ice cream 0:15
[INAUDIBLE] you guys [INAUDIBLE] you guys know this song right come on [LAUGH] Okay, 0:19
so, I have two arrays. 0:24
I have a sweet flavor and I have a savory flavor and these are actually real. 0:27
They really do have barbecue sauce and they really do have baked beans. 0:31
So, what we're going to do is we're going to mix these two together. 0:35
And we're going to do that through nesting two for loops. 0:39
So let's go ahead and we'll say, we're gonna use the for each loop here. 0:42
For each of the sweets, the sweet flavors. 0:46
And then we want every single one of the sweet ones to mix with the other ones. 0:50
We wanna see all the possible combinations that we can make with this so 0:53
we're gonna nest the loop. 0:56
So, another for loop. 0:57
So each time, each one of these we're gonna run another one of these loops. 0:59
You see this quite a bit, and sometimes it's using the Is and the Js. 1:01
I keep on pressing tab, I've been moved into the IDE world in writing these 1:06
courses and I've been pressing tab. 1:10
Say %s and %s. 1:15
And we're going to pass in the sweet and we're going to pass in the savory. 1:18
Okay. So let's run it and 1:24
then we'll take a look at, we'll walk it really quick. 1:25
Love that I have a java ice cream. 1:32
Alright. 1:35
Okay, so this is the one that popped out here, this very last one here. 1:39
This is the barbecue sauce. 1:44
And let's see if I can make this actually longer. 1:46
Let's see the whole thing. 1:48
And I'll bring the loop back down. 1:52
Nope, all right, so alright, so 1:53
caramel is the first sweet flavor. 1:58
So what's gonna happen is it's gonna go into this for loop and 2:03
sweet is gonna be set to caramel. 2:05
Next, we're gonna loop through each one of the savory ones but 2:09
we're gonna keep sweet because it's in the top loop. 2:11
And then in the inside loop we're gonna hit savory. 2:13
Does that make sense? 2:17
It happens quite a bit when you need to do cross-products of things and 2:18
combinations of, you want to loop through all of these and 2:21
see what happens if you do a combination with all of these things. 2:24
So it's a nested for loop. 2:27
I just wanted to show you that cause you will see those. 2:28