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Let's explore how to loop through all elements in the array using a for each approach.
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[MUSIC]
0:00
So now we have a single variable
that can store multiple elements.
0:04
We can pass that variable around, store it
as a field on an object, but then what?
0:08
In your coding journey, you'll find
that one of the most common tasks in
0:12
programming involves
looping through your data.
0:16
You'll process each and
every value in your data.
0:18
Arrays are wonderful to use for loops.
0:21
So let's go get familiar with them.
0:24
All right, so let's get coding.
0:26
I have attached a new work space here and
there is a file called Explore.java.
0:28
It's got the main boiler plate
0:33
Java application program
already written for you.
0:36
You're welcome.
0:39
So let's take our same
movie theater example
0:40
of getting all these friends together.
0:43
Let's imagine for a second that group
texting doesn't exist because I'm old, and
0:45
I still use one of those flip phones.
0:49
But I wanna send everyone
a text with the movie showtime.
0:51
So let's do this,
let's recreate that friends array here.
0:54
Well, actually, why don't you do it?
0:58
Why don't you use the shortcut method
that you can do when declaring and
1:00
initializing in a single line.
1:04
Here, let's do this,
I'll type out the instructions, let's see.
1:06
Create a new friends array using
the array literal shortcut.
1:10
Include Ben, Alena, and Pasan.
1:18
Okay, pause me, do it and
then unpause me to review how I did it.
1:26
Ready?
1:30
How did you do?
1:32
Here's what I did.
1:33
Made a new string array called friends and
1:35
I added Ben, Alena and Pasan.
1:41
So we want to basically write
a personalized text message to each person
1:49
in our friends array.
1:53
We'll just write out to the console,
but you get the idea.
1:55
Would you wanna process every element in
the array, a great solution to reach for
1:58
is the enhanced for loop.
2:03
The way the enhanced for
loop works is pretty straight forward, so
2:05
first you type the keyword, for.
2:09
Now much like if statements, for
2:12
statements are followed by an expression
which is surrounded by parenthesis.
2:14
And then after you've defined
your expression, again,
2:19
much like an if statement, you open your
block of code with a curly brace and
2:22
close it with a closing curly brace.
2:26
In the enhanced for form,
the expression is pretty clean and clear.
2:29
So what you do first is you declare a new
2:34
variable that you would like
to use within your code block.
2:37
So we're gonna call that String friend.
2:41
And then we're gonna prep the colon and
then friends.
2:45
So this can be read as for
each friend in friends.
2:51
Processing each element of a collection
like this is known as iterating.
2:57
And we are iterating
over our friends array.
3:01
An array is able to be iterated on.
3:05
Or more commonly stated,
arrays are iterable.
3:07
The way that the enhanced for loop works
is that anything that you place over here
3:11
on the right side must be iterable.
3:16
We'll get into how to ensure
that in a future course but for
3:19
now just know that arrays meet
that criteria, they are iterable.
3:23
So, now that we have each element
in the array available on each
3:27
iteration though this loop, we can use it.
3:32
So let's send our pretend text
to each of our friends so,
3:35
let's just use a formatted string, right?
3:40
So let's say System.out.printf,
3:43
let's see, hey %s, the movie starts at 7.
3:49
And remember these flip phones
are hard to type on, so
3:55
I'm just gonna do a C, and a U, and there.
3:58
All right, and
then we're gonna do a new line, %n, cool.
4:00
I'm gonna pass in friend, right?
4:04
Cuz that's what we want to
go in where that %s is.
4:10
So again,
4:13
this friend here is being changed
on each iteration through the loop.
4:14
Each and
every string in this array will run.
4:20
Here, so let's run it.
4:22
So what we'll do is we'll
make sure that this is saved.
4:23
And we'll say clear.
4:27
And javac Explore.java,
4:28
don't need to do that clear but
I like to clear the console before hand.
4:32
And java Explore, and
then that way we can use the up arrow.
4:37
There we go.
We should see, there we go, hey Ben,
4:41
hey Alena, hey Pasan.
4:45
Awesome, so this is pretty clear and
concise, isn't it?
4:47
When you need to process all items in an
array, this enhanced for loop is the way
4:52
to go, and it is the recommended approach
because of how clear it is, right?
4:57
Now you probably notice that this
is called the enhanced for loop.
5:03
So what is this unenhanced for loop then?
5:07
Well, it's just called a for loop,
and let's take a look at that next.
5:10
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