Add element to array associative arrays

Question

All examples of adding new elements to associative arrays are going the "easy" way and just have a one dimensional array - my problem of understanding is having arrays within arrays (or is it objects in arrays?).

I have the following array:

var test = [
            {
                value: "FirstVal",
                label: "My Label 1"
            },
            {
                value: "SecondVal",
                label: "My Label 2"
            }
           ];

Two questions: How to generate this array of associative arrays (yes... object) from scratch? How to add a new element to an existing array?

Thanks for helping me understand javascript.

This might be useful: [Javascript: Adding to an associative array](http://stackoverflow.com/questions/8328508/javascript-adding-to-an-associative-array/8328541#8328541) — jabclab, Dec 19 '11 at 14:15
Bad wording... "from scratch" simply meaning - new. Basically it is the same as starting with an empty array and adding elements to it - your replies already answer this :-) — Dennis G, Dec 19 '11 at 14:18

score 10 · Accepted Answer · answered Dec 19 '11 at 14:15

I'm not exactly sure what you mean by "from scratch", but this would work:

var test = [];  // new array

test.push({
                value: "FirstVal",
                label: "My Label 1"
            });  // add a new object

test.push({
                value: "SecondVal",
                label: "My Label 2"
            });  // add a new object

Though the syntax you posted is a perfectly valid way of creating it "from scratch".

And adding a new element would work the same way test.push({..something...});.

score 4 · Answer 2 · answered Dec 19 '11 at 14:14

4

This is an array of objects.

You can put more objects in it by calling test.push({ ... })

answered Dec 19 '11 at 14:14

SLaks

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"array of objects" - thanks for clarifying! Basically non-named objects, because of the {}? – Dennis G Dec 19 '11 at 14:21
1

@moontear: There is no such thing as a "named object". – SLaks Dec 19 '11 at 14:21

score 2 · Answer 3 · answered Dec 19 '11 at 14:24

var items = [{name:"name1", data:"data1"}, 
             {name:"name2", data:"data2"}, 
             {name:"name3", data:"data3"}, 
             {name:"name4", data:"data4"}, 
             {name:"name5", data:"data5"}]

var test = [];

for(var i = 0; i < items.length; i++){
    var item = {};
    item.label = items[i].name;
    item.value = items[i].data;
    test.push(item);
}

makes test equal to

[{label:"name1", value:"data1"}, 
 {label:"name2", value:"data2"}, 
 {label:"name3", value:"data3"}, 
 {label:"name4", value:"data4"}, 
 {label:"name5", value:"data5"}]

Rob W · Answer 4 · 2011-12-19T14:25:41.930

1

From scratch, the following lines will create an populate an array with objects, using the Array.prototype.push method:

var test = [];          // Create an array
var obj = {};           // Create an object
obj.value = "FirstVal"; // Add values, etc.
test.push(obj);

edited Dec 19 '11 at 14:25

answered Dec 19 '11 at 14:14

Rob W

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Please fix your script to use newobj too – mplungjan Dec 19 '11 at 14:22

Add element to array associative arrays

4 Answers4