Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Working with arrays

From: Foundations of Programming: Fundamentals

Video: Working with arrays

An array is a collection of values all wrapped up and given a name. Okay, so what does that mean? Well, we already know how to create one variable at a time. We use the word var, we give it a name, and then we can use the equal sign to give that variable a value. That could be a letter, it could be a number, it could be a string, it could be a Boolean, but it's one value. Now an array is the idea of multiple values but all contained in one named variable such as this one.

Working with arrays

An array is a collection of values all wrapped up and given a name. Okay, so what does that mean? Well, we already know how to create one variable at a time. We use the word var, we give it a name, and then we can use the equal sign to give that variable a value. That could be a letter, it could be a number, it could be a string, it could be a Boolean, but it's one value. Now an array is the idea of multiple values but all contained in one named variable such as this one.

We have a variable called myArray with multiple values in it. It's a great way to keep data together that belongs together, to keep dozens, hundreds, or even thousands of pieces of information together without having to name every single individual piece as an individual variable. But before we make one, here are a couple of concepts. See if all we have is one name for this entire array, how do we get individual pieces in or out? Well in an array each individual value, often referred to as an element, has a number, an index that identifies where it is in the array.

Arrays have an internal order. Tey don't shuffle their values around randomly. So the first slot has an index of 0, the second slot or second position has an index of 1, third slot is 2, and so on. So I have got an array with seven elements in it here but there is no minimum or maximum size. You can make arrays as big as you need them. You are simply limited by the amount of memory you have available. In JavaScript, like most languages these days, arrays are zero-based and that means the first position, the first element in the array, is considered to be at position 0, not position 1.

In some languages like older versions of Visual Basic used 1-based arrays but 0-based arrays are far more common. So we can use that number, that index to either set that value or to get to that value. So I need to use both the name of the array and the index of the element to access any one part of the array. So let's make one. In JavaScript, we can make the variable the same way we always do it, but we need to tell JavaScript this is an array.

There is actually a few ways to do it, but this is the easiest one. We'll use the word var and I'm going to call my variable multipleValues. You can call it whatever you like. Then we will use the equal sign and then what we are going to use is this opening square bracket and closing square bracket, and this is the indicator that we're dealing with an array, not a single value. When you see those square brackets in JavaScript, it's a pretty good sign you have got an array somewhere. So this line and these characters here simply create a single variable called multipleValues that you can put a bunch of stuff inside.

Well how do you do that, how do I get to the individual elements of that array? I use these square brackets again. So if I want this array to hold multiple values we need to be able to say which element of the array are we trying to get to? So we use the index. So here is an example. I use the name of the variable but instead of just saying equals, I am using those square brackets again. I'm saying here I want the element at position 0 to be set to the value 50 and I want the element at position 1 to be set to the value 60.

I can say I want the element of position 2 to be able to the word "Hello" and notice that what I can do in this array is I can put in a number, I can put in a string, I could also put in a Boolean, I can actually put anything in there. It doesn't matter what kind of data you're putting in at the different slots in the array, but all of them are accessed using that index and that's whether you are setting these values or whether you're getting these values. It's always a 0-based index.

Now what we can then do is use the same format to get to the contents of the array. So for example, if I want to write an alert message with whatever is at the second position I use the square brackets. I use the same way to access them and to set them and it writes out the word "Hello" in this case. So if this is the way that we write arrays. It's okay, it's not too bad, but it would be nice if there was something a little quicker, and in fact there is. There is a shorthand method for doing it.

So instead of doing it over several statements like this, we can use those square brackets and combine all this stuff onto one line. We can just load this array up with the initial values. In this case, 50, 60, "Hello", and it will automatically create an array and put them in that position 0, position 1, position 2. You could then come along and add position 3, position 4, and so on but it's always a 0-based index. Now arrays are found in every language, and as we will see there are other ways of grouping values together.

Sometimes you might not want a 0-based index but perhaps a letter-based index or some other way of accessing the elements of the array. And we can do that too. But these arrays are the classic way to get started with what we are often referred to as collections in a programming language, and this time the buzz word really is straightforward. A collection in a programming language is simply multiple values grouped together in some way, and there are often slightly different ways of creating them across languages but the overall concept is the same.

Show transcript

This video is part of

Image for Foundations of Programming: Fundamentals
Foundations of Programming: Fundamentals

61 video lessons · 84668 viewers

Simon Allardice
Author

 
Expand all | Collapse all
  1. 4m 14s
    1. Welcome
      1m 16s
    2. Making the most of this course
      2m 8s
    3. Using the exercise files
      50s
  2. 22m 11s
    1. What is programming?
      5m 45s
    2. What is a programming language?
      4m 48s
    3. Writing source code
      5m 34s
    4. Compiled and interpreted languages
      6m 4s
  3. 16m 29s
    1. Why JavaScript?
      4m 45s
    2. Creating your first program in JavaScript
      6m 54s
    3. Requesting input
      4m 50s
  4. 31m 38s
    1. Introduction to variables and data types
      5m 16s
    2. Understanding strong, weak, and duck-typed languages
      3m 51s
    3. Working with numbers
      5m 4s
    4. Using characters and strings
      4m 5s
    5. Working with operators
      4m 47s
    6. Properly using white space
      6m 46s
    7. Adding comments to code for human understanding
      1m 49s
  5. 24m 49s
    1. Building with the if statement
      7m 35s
    2. Working with complex conditions
      4m 10s
    3. Setting comparison operators
      6m 59s
    4. Using the switch statement
      6m 5s
  6. 17m 56s
    1. Breaking your code apart
      4m 1s
    2. Creating and calling functions
      2m 57s
    3. Setting parameters and arguments
      6m 7s
    4. Understanding variable scope
      2m 23s
    5. Splitting code into different files
      2m 28s
  7. 13m 32s
    1. Introduction to iteration
      4m 28s
    2. Writing a while statement
      5m 24s
    3. Creating a for loop
      3m 40s
  8. 19m 28s
    1. Cleaning up with string concatenation
      4m 30s
    2. Finding patterns in strings
      8m 3s
    3. Introduction to regular expressions
      6m 55s
  9. 19m 59s
    1. Working with arrays
      5m 47s
    2. Array behavior
      5m 29s
    3. Iterating through collections
      5m 18s
    4. Collections in other languages
      3m 25s
  10. 10m 50s
    1. Programming style
      5m 55s
    2. Writing pseudocode
      4m 55s
  11. 25m 55s
    1. Input/output and persistence
      3m 6s
    2. Reading and writing from the DOM
      8m 11s
    3. Event driven programming
      7m 47s
    4. Introduction to file I/O
      6m 51s
  12. 24m 26s
    1. Introduction to debugging
      5m 57s
    2. Tracing through a section of code
      7m 5s
    3. Understanding error messages
      3m 21s
    4. Using debuggers
      8m 3s
  13. 14m 17s
    1. Introduction to object-oriented languages
      5m 18s
    2. Using classes and objects
      6m 29s
    3. Reviewing object-oriented languages
      2m 30s
  14. 11m 14s
    1. Memory management across languages
      5m 11s
    2. Introduction to algorithms
      4m 2s
    3. Introduction to multithreading
      2m 1s
  15. 29m 20s
    1. Introduction to languages
      1m 42s
    2. C-based languages
      4m 40s
    3. The Java world
      3m 13s
    4. .NET languages: C# and Visual Basic .NET
      6m 17s
    5. Ruby
      3m 4s
    6. Python
      2m 56s
    7. Objective-C
      4m 3s
    8. Libraries and frameworks
      3m 25s
  16. 1m 2s
    1. Where to go from here
      1m 2s

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ.

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Join now "Already a member? Log in

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed Foundations of Programming: Fundamentals.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferencesfrom the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Are you sure you want to delete this note?

No

Your file was successfully uploaded.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.