How do I create an Array into another Array?

Question

I have the following JavaScript Array:

var jsonArray = { 'homes' : 
[
 {
 "home_id":"203",
 "price":"925",
 "sqft":"1100",
 "num_of_beds":"2",
 "num_of_baths":"2.0",
 },
 {
 "home_id":"59",
 "price":"1425",
 "sqft":"1900",
 "num_of_beds":"4",
 "num_of_baths":"2.5",
 },
 // ... (more homes) ... 
]}

I want to convert this to the following type of Array (pseudo code):

var newArray = new Array();
newArray.push(home_id's);

How can I do that?

Notice how the newArray only has home_ids from the big jsonArray array.

• Sean Kinsey: jsonArray is not an array, its an object - jsonArray.homes is one though.

Answer 1

Just make a new array and copy the old values in.

var ids = [];
for (var i = 0; i < jsonArray.homes.length; i++) {
 ids[i] = jsonArray.homes[i].home_id;
}

• DannyLane: +1 I was looking at this wondering how I used to do it in c# before linq :)

Answer 2

Again, jsonArray is not an array but an object, but jsonArray.homes is

var arr = [];
for (var i=0, len = jsonArray.homes.length; i < len; i++){
 arr.push(jsonArray.homes[i].home_id);
} 

Answer 3

Here's one iterative way:

function getPropertyValues (array, id) {
 var result = [];
 for ( var hash in array ) {
 result.push( array[hash][id]);
 }
 return result;
}
var home_ids = getPropertyValues(jsonArray.homes, "home_id");

Or if you want to do it real quick and dirty (and you are only targeting modern Javascript capable engines):

var home_ids = jsonArray.homes.map( function(record) { return record.home_id } );

• Justin Johnson: You shouldn't use for..in to iterate over an array, but if you're going to, you need to at least check hasOwnProperty