Javascript (back to basics) arrays?

Question

Can someone please help me. I have been writing javascript and jquery for over a year now, but there is one topic I have never run across. ARRAYS. can someone give me a basic idea on how arrays in javascript work and how I can use them. I am trying to store an array of arrays that contain strings. Like this

• Base Array
  • [0] Sub Array
    • [0] 'Hello World'
    • [1] 'Hey What's Up World'
  • [1] Sub Array
    • [0] 'Hello America'
    • [1] 'Hello UK'

And I might also have some numeric values in there too. So, how can I go about this task.

Answer 1

var array = [
  ['Hello World', "Hey What's Up World"],
  ['Hello America', 'Hello UK'],
  [1, 2, 3]
];

array[0][1]; // "Hey What's Up World"
array[2][2]; // 3

Answer 2

Like this:

var array = [
              [ 'Hello World', 'Hey What Up World' ],
              [ 'Hello America', 'Hello UK' ]
            ];

Answer 3

keep in mind that Arrays in javascript can be both numeric and hash, as in...

var foo = new Array();
foo[0] = "a";
foo[1] = "b";

etc...

or

foo["key1"] = "a";
foo["key2"] = "b";

The primary difference here is that if you use it in the hash context, you can't get a length (array.length) as it will always be 0. However, if you want to loop through your hash you can do it like this:

for(myKey in foo){
  ...
}

where mykey will take on the key and you can get the value by using foo[mykey], in the above loop.

You can also loop this way through a numeric array, in which case myKey will just run through all the numbers.

Lastly, if you arbitrarily stick something into a high numbered element as in...

foo = new Array();
foo[1000] = "what happened to the first 999";

0 - 999 will all be initialized to null, but the length of this array will now immediately be 1001;

As to adding multiple dimensions, since every item in the array is just an Object, it can hold whatever you want it to, including another Array.

Hope that helps.