Associative arrays in Javascript?

Question

Currently, I am creating a 3d array in js using the following:

var arr = [["name1", "place1", "data1"],
          ["name2", "place2", "data2"],
          ["name3", "place3", "data3"]];

I can access each element using arr[0] or arr[1]. But is there anyways I can access them using a key like this: arr["name1"] should give me the first one. Any suggestions? I think I am looking for a Hashmap like functionality.

Answer 1

The only way you could do that is by wrapping it in an object.

var arr = {
    name1 : ["name1", "place1", "data1"],
    name2 : ["name2", "place2", "data2"],
    name3 : ["name3", "place3", "data3"]
};

Answer 2

Javascript is a prototype based dynamic language. You can create objects and change their structure when you want.

var o = {name1: {place1: data1}, name2: {place2: data2}};

and access it with:

o.name1

The look-up implementation varies though and when you have a lot of properties that often changes this can be pretty slow (except in Chrome that uses a special scheme to access object properties i.e. embedded classes a-la-dynamic dispatch from smalltalk). Some libraries (e.g. MooTools) provide some hash map related structures,