Understanding Multidimensional Arrays for Coding with JavaScript

Not only can you store arrays inside of arrays with JavaScript, you can even put arrays inside of arrays inside of arrays. This can go on and on. An array that contains an array is called a multidimensional array. To write a multidimensional array, you simply add more sets of square brackets to a variable name. For example:

var listOfLists[0][0];

Multidimensional arrays can be difficult to visualize when you first start working with them.

A pictorial representation of a multidimensional array.

You can also visualize multidimensional arrays as hierarchal lists or outlines. For example:

Top Albums by Genre

1. Country

   Johnny Cash:Live at Folsom Prison

   Patsy Cline:Sentimentally Yours

   Hank Williams:I’m Blue Inside

2. Rock

   T-Rex:Slider

   Nirvana:Nevermind

   Lou Reed:Transformer

3. Punk

   Flipper:Generic

   The Dead Milkmen:Big Lizard in My Backyard

   Patti Smith:Easter

Here is a code that would create an array based on what you see above:

var bestAlbumsByGenre = []
bestAlbumsByGenre[0] = "Country";
bestAlbumsByGenre[0][0] = "Johnny Cash:Live at Folsom Prison"
bestAlbumsByGenre[0][1] = "Patsy Cline:Sentimentally Yours";
bestAlbumsByGenre[0][2] = "Hank Williams:I’m Blue Inside";
bestAlbumsByGenre[1] = "Rock";
bestAlbumsByGenre[1][0] = "T-Rex:Slider";
bestAlbumsByGenre[1][1] = "Nirvana:Nevermind";
bestAlbumsByGenre[1][2] = "Lou Reed:Tranformer";
bestAlbumsByGenre[2] = "Punk";
bestAlbumsByGenre[2][0] = "Flipper:Generic";
bestAlbumsByGenre[2][1] = "The Dead Milkmen:Big Lizard in my Backyard";
bestAlbumsByGenre[2][2] = "Patti Smith:Easter";