In our continuing saga of data types, we now turn our attention to arrays. Arrays are more complex than the previous data types we have discussed, but are utilized quite often and handy when it comes to accessing large amounts of data.
Here is how they work…
Arrays are created and stored in a single variable, which allows for ease of access…
[code lang=”js”]
var cars = new Array();
[/code]
Now we have an array entitled ‘car’ that we can use in our code. There is one problem…it is empty. We have to fill it with data.
Arrays allow you to store multiple pieces of data within the single variable. We can do this using what are called ‘keys’, which denote elements of the array. Let’s take a look at code for an explanation…
[code lang=”js”]
cars[0] = "Chevy";
cars[1] = "Ford";
cars[2] = "Dodge";
[/code]
So, as you can see, I now have three pieces of information contained within my cars variable. Each piece of information, or element, is denoted by a number key. So the first item, ‘Chevy’, is stored in the first position of the array…cars[0].
Now I know what you may be thinking, “You said that is the first position. WHat is with the zero?” Good catch! Arrays are called zero-based, which means they start counting from zero. That is important to remember when we begin working with the array. For example, if I want the second array element, I would need to use cars[1], not cars[2], which would be the third.
Sometimes folks just starting to work with arrays have some initial difficulty in grasping the concept. Here is another way of thinking of it. An array is similar to an accordion file folder. One unit with many slots. You can put items in various slots (elements) within the file folder, but it is still one file folder.
On a related note, there are arrays known as multi-dimensional arrays. These are arrays within arrays. So you would store one array inside another. i.e. put one accordion file folder within a separate accordion file folder.
I think you will find arrays useful and utilize them a ton in your programming. Happy Coding!
