why does my json have square brackets?

I'm investigating json with jquery and mvc2. I'm trying to create some json for an ajax post to my controller. I have an array created by this function

function getArguments() {
var argument1 = urlarray.slice(2, 3);
var argument2 = urlarray.slice(3, 4);
var argument3 = urlarray.slice(4, 5);
var argument4 = urlarray.slice(5);

return { Argument1: argument1, Argument2: argument2, Argument3: argument3, Argument4: argument4 }
}

I'm using json2.js to create the json like so

var data = getArguments();
var json = JSON.stringify(data);

when I look at the json it looks like this:

{"Argument1":["16"],"Argument2":["2"],"Argument3":["True"]}

This looks开发者_StackOverflow中文版 like valid json, but I don't understand the square brackets. I thought that was an array... anyone know why json2.js and its stringify would be putting in these brackets?... feel like I'm missing something obvious here.

---

.slice() returns an array, even though you're slicing out only single values. Try something like:

var argument1 = urlarray[2];
var argument2 = urlarray[3];
etc...

which would return whatever's stored in those array slots (integer)?)