How can I create a javascript associative array { } with dynamic key names?

Question

Basically I have a loop incrementing i, and I want to do this:

var fish = { 'fishInfo[' + i + '][0]': 6 };

however it does not work.

Any ideas how to do this? I want the result to be

fish is { 'fishInfo[0][0]': 6 };
fish is { 'fishInfo[1][0]': 6 };
fish is { 'fishInfo[2][0]': 6 };

etc.

I am using $.merge to combine them if you think why on earth is he doing that :)

What's wrong with either (a) just creating an array; or (b) using a loop to generate the counter? What is the problem you are having? — Marcin, Jan 6 '12 at 12:42

nikc.org · Accepted Answer · 2012-01-06 12:43:06Z

up vote 7 down vote accepted

Declare an empty object, then you can use array syntax to assign properties to it dynamically.

var fish = {};

fish[<propertyName>] = <value>;

answered Jan 6 '12 at 12:43

nikc.org
6,74811139

1

Cheers this sorted it. And I needed $.extend instead of $.merge :) – SLC Jan 6 '12 at 13:17

Tadeck · Answer 2 · 2012-01-06 13:02:41Z

Do this:

var fish = {};
fish['fishInfo[' + i + '][0]'] =  6;

It works, because you can read & write to objects using square brackets notation like this:

my_object[key] = value;

and this:

alert(my_object[key]);

jAndy · Answer 3 · 2012-01-06 12:42:50Z

up vote 2 down vote

For any dynamic stuff with object keys, you need the bracket notation.

var fish = { };

fish[ 'fishInfo[' + i + '][0]' ] = 6;

answered Jan 6 '12 at 12:42

jAndy
81.9k11123188

Kevin Bowersox · Answer 4 · 2012-01-06 12:49:04Z

Multidimensional Arrays in javascript are created by saving an array inside an array.

Try:

var multiDimArray = [];
for(var x=0; x<10; x++){
    multiDimArray[x]=[];
    multiDimArray[x][0]=6;
}

4 Answers