Actionscript :: Setting Object Keys?

If I have an array, I can set the keys by doing the following:

var example:Array = new Array();

example[20] = "500,45";
example[324] = "432,23";

If I want to do something with Objects, how would I achieve this?I tried the following:

var example:Object = [{x:500, y:45}, {x:432, y:23}]; // Works but keys are 0 and 1
var example:Object = [20: {x:500, y:45}, 324: {x:432, y:23}]; // Compile errors
var example:Object = [20]: {x:500, y:45}, [324]: {x:432, y:23}; // Compile errors
var example:Object = [20] {x:500, y:45}, [324] {x:432, y:23}; // Compile errors

I understand I could do this:

var example:Object = {id20 : {x:500, y:45}, id324: {x:432, y:23} };

But it doesn't suit me.