Heads up! To view this whole video, sign in with your Courses account or enroll in your free 7-day trial. Sign In Enroll
Preview
Start a free Courses trial
to watch this video
Let's explore a handy way to create arrays when you know all the values at creation time.
We currently have two array
examples that we've been exploring.
0:00
They're pretty similar but
slightly different.
0:03
Now first, we have golf scores.
0:06
We know that we have a fix
number of holes, 18.
0:07
But we don't know what those scores are
the moment that we create scores array.
0:11
Our other example,
the friends going to a movie together.
0:16
We actually do note who
the friends are at creation time.
0:19
Now when you know all
the values of an array,
0:22
you really should use what is
known as an array literate.
0:24
It saves a lot of typing and
it's actually quite concise.
0:27
You're gonna love it.
0:30
Let's go take a look.
0:31
So go ahead and get your workspace up and
running with jshell.
0:32
The declaration of the array
actually still looks the same.
0:36
So we have a String of friends.
0:40
Now what looks different is
the way that we set the values.
0:42
So what we do is we open
up with a curly brace, and
0:45
let me type in the values
separated by comas.
0:48
Now, note that these are curly braces
other programming languages tend to
0:55
represent this bit here as a hard bracket,
but Java uses curly braces.
1:01
Now, that's pretty clear, isn't it?
1:06
So, it sets each index in the order
of the values here, right.
1:09
So this is 0, 1, 2, right?
1:13
So, we can do friends 0, get the first
one out, and then it's gonna be Pasan.
1:15
And we can use the up arrow, we can look
and we can get Alena out too, right.
1:22
And also,
what happens is it automatically get set,
1:27
the length to the amount that
you passed in, automatically.
1:31
Pretty handy, right?
1:36
So one thing I wanted to point
out that this declaring and
1:37
initializing on the same line,
gave us some extra powers.
1:40
If you declare that array first and
1:44
don't initialize it, you need to also
declare its type, so let's do that.
1:46
So, let's say that I wanted to
get snacks from the snack, so
1:51
we're gonna have an array of snack
name and so we'll call it snacks.
1:54
Okay, and I'm not gonna initialize it,
just declare it.
1:58
And then later let's say
that I wanted to use it.
2:01
Now, one would assume that you
can probably just say snacks =,
2:03
let's see, we wanna gonna get nachos.
2:09
We want some Sour Patch Kids, obviously,
2:13
probably need that Snickers, and
I think we need a large popcorn.
2:17
Here we go, that sounds good.
2:24
So you would think that
you could just do this,
2:26
but what you'll see is you'll get
this illegal start of expression.
2:29
So this'll happen to you for sure.
2:33
Now, what's happened here is on the one
liner this type has been inferred,
2:34
it could figure it out automatically.
2:40
Here though not so much,
but here's the work around.
2:43
So I'm gonna go ahead,
I'm gonna press the up arrow.
2:45
And I will preface this,
move our cursor over here,
2:49
we're gonna preface this
with a new string array.
2:53
Here we go, and now it knows the type and
now it will work fine.
3:01
So this typed literal
style is also a great way
3:05
to pass an array into a method that
takes an array as a parameter.
3:08
This way you don't need to create
a new variable, you can just do this.
3:12
You can just say new string and then
curly braces the values, there you go.
3:15
That you way,
you wouldn't need to create a variable.
3:20
And it makes an anonymous or
unnamed array for you.
3:22
Well, we'll explore this in a bit.
3:26
This next looks so good.
3:28
I guess I should've asked
the others what they wanted.
3:30
So now that we know how to declare,
initialize, and
3:33
access elements of the array, we are ready
to start using them more programmatically.
3:36
We have this wonderful
populated data structure
3:41
now all stored in a single variable.
3:44
Why don't we start looping through it
showing off one of its main benefits.
3:45
You need to sign up for Treehouse in order to download course files.
Sign up