Hash keys / values as array

I cannot find the JavaScript equivalent of PHP array_keys() / array_values().

For people unfamiliar with PHP given the following JavaScript hash:

var myHash = {"apples": 3, "oranges": 4, "bananas": 42}

How can I get an array of keys, i.e.,

["apples", "oranges", "bananas"]

The same question with the values, i.e.,

[3, 4, 42]

jQuery can be used.

In ES5 supported (or shimmed) browsers...

var keys = Object.keys(myHash);

var values = keys.map(function(v) { return myHash[v]; });

---

Shims from MDN...

• Object.keys

• Array.prototype.map

var a = {"apples": 3, "oranges": 4, "bananas": 42};    

var array_keys = new Array();
var array_values = new Array();

for (var key in a) {
    array_keys.push(key);
    array_values.push(a[key]);
}

alert(array_keys);
alert(array_values);

The second answer (at the time of writing) gives:

var values = keys.map(function(v) { return myHash[v]; });

But I prefer using jQuery's own $.map:

var values = $.map(myHash, function(v) { return v; });

Since jQuery takes care of cross-browser compatibility. Plus it's shorter :)

At any rate, I always try to be as functional as possible. One-liners are nicers than loops.

Look at the _.keys() and _.values() functions in either Lodash or Underscore.js:

• Underscore.js _.keys
• Underscore.js _.values
• Lodash _.keys
• Lodash _.values

function getKeys(obj){
    var keys = [];
    for (key in obj) {
        if (obj.hasOwnProperty(key)) { keys[keys.length] = key; }
    } 
    return keys;
}

I don't know if it helps, but the "foreach" goes through all the keys:

for (var key in obj1) {...}

Here are implementations from phpjs.org:

• array_values
• array_keys

This is not my code. I'm just pointing you to a useful resource.

Use:

var myHash = {"apples": 3, "oranges": 4, "bananas": 42}
vals=(function(e){a=[];for (var i in e) a.push(e[i]); return a;})(myHash).join(',')
keys=(function(e){a=[];for (var i in e) a.push(  i ); return a;})(myHash).join(',')
console.log(vals,keys)

Basically:

array=(function(e){a=[];for (var i in e) a.push(e[i]); return a;})(HASHHERE)

Here is a good example of array_keys from PHP.js library:

function array_keys (input, search_value, argStrict) {
    // Return just the keys from the input array, optionally only for the specified search_value

    var search = typeof search_value !== 'undefined',
        tmp_arr = [],
        strict = !!argStrict,
        include = true,
        key = '';

    for (key in input) {
        if (input.hasOwnProperty(key)) {
            include = true;
            if (search) {
                if (strict && input[key] !== search_value) {
                    include = false;
                }
                else if (input[key] != search_value) {
                    include = false;
                }
            }

            if (include) {
                tmp_arr[tmp_arr.length] = key;
            }
        }
    }

    return tmp_arr;
}

The same goes for array_values (from the same PHP.js library):

function array_values (input) {
    // Return just the values from the input array

    var tmp_arr = [],
        key = '';

    for (key in input) {
        tmp_arr[tmp_arr.length] = input[key];
    }

    return tmp_arr;
}