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Array Literal Shortcut
3:49Let'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.
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They're pretty similar but
slightly different.
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Now first, we have golf scores.
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We know that we have a fix
number of holes, 18.
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But we don't know what those scores are
the moment that we create scores array.
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Our other example,
the friends going to a movie together.
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We actually do note who
the friends are at creation time.
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Now when you know all
the values of an array,
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you really should use what is
known as an array literate.
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It saves a lot of typing and
it's actually quite concise.
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You're gonna love it.
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Let's go take a look.
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So go ahead and get your workspace up and
running with jshell.
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The declaration of the array
actually still looks the same.
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So we have a String of friends.
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Now what looks different is
the way that we set the values.
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So what we do is we open
up with a curly brace, and
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let me type in the values
separated by comas.
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Now, note that these are curly braces
other programming languages tend to
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represent this bit here as a hard bracket,
but Java uses curly braces.
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Now, that's pretty clear, isn't it?
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So, it sets each index in the order
of the values here, right.
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So this is 0, 1, 2, right?
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So, we can do friends 0, get the first
one out, and then it's gonna be Pasan.
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And we can use the up arrow, we can look
and we can get Alena out too, right.
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And also,
what happens is it automatically get set,
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the length to the amount that
you passed in, automatically.
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Pretty handy, right?
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So one thing I wanted to point
out that this declaring and
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initializing on the same line,
gave us some extra powers.
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If you declare that array first and
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don't initialize it, you need to also
declare its type, so let's do that.
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So, let's say that I wanted to
get snacks from the snack, so
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we're gonna have an array of snack
name and so we'll call it snacks.
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Okay, and I'm not gonna initialize it,
just declare it.
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And then later let's say
that I wanted to use it.
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Now, one would assume that you
can probably just say snacks =,
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let's see, we wanna gonna get nachos.
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We want some Sour Patch Kids, obviously,
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probably need that Snickers, and
I think we need a large popcorn.
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Here we go, that sounds good.
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So you would think that
you could just do this,
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but what you'll see is you'll get
this illegal start of expression.
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So this'll happen to you for sure.
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Now, what's happened here is on the one
liner this type has been inferred,
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it could figure it out automatically.
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Here though not so much,
but here's the work around.
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So I'm gonna go ahead,
I'm gonna press the up arrow.
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And I will preface this,
move our cursor over here,
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we're gonna preface this
with a new string array.
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Here we go, and now it knows the type and
now it will work fine.
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So this typed literal
style is also a great way
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to pass an array into a method that
takes an array as a parameter.
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This way you don't need to create
a new variable, you can just do this.
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You can just say new string and then
curly braces the values, there you go.
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That you way,
you wouldn't need to create a variable.
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And it makes an anonymous or
unnamed array for you.
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Well, we'll explore this in a bit.
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This next looks so good.
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I guess I should've asked
the others what they wanted.
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So now that we know how to declare,
initialize, and
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access elements of the array, we are ready
to start using them more programmatically.
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We have this wonderful
populated data structure
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now all stored in a single variable.
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Why don't we start looping through it
showing off one of its main benefits.
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