removing the key from a key value pair of objects in javascript

Question

Let's say I have this Array of objects:

[300: {a:"some", b:"value"}, 301: {a: "another", b: "val"} ...]

I have that kind of object and I am iterating using recursive function, and there's no way I will change my counter to start at 300, I always start at 0.

I am thinking of a solution, to remove the keys from the agrray so that I will have an array like so:

[{a:"some", b:"value"}, {a: "another", b: "val"} ...]

How do I do that in javascript? Also, if there is another way that would be much faster than creatng a function that will remove keys, it will be much better.

You know that what you have is just an Array, with attributes 300, 301, etc, right? — thefourtheye
– thefourtheye, Commented Apr 5, 2014 at 14:45
ahh, yes, it'll be much better to use the word Array, thank you — Joey Hipolito
– Joey Hipolito, Commented Apr 5, 2014 at 14:47
Actually your expected output is an Array of objects, but your actual Array has no elements at all. — thefourtheye
– thefourtheye, Commented Apr 5, 2014 at 14:48
I think you misunderstand, @JoeySalacHipolito. That first thing is an object with a bunch of key/values, not an array. You've just used the wrong syntax. It should be { 300: {}... }. Try plugging that into the console and you'll get a syntax error. — Andy
– Andy, Commented Apr 5, 2014 at 14:50
uhmm, but still I used that format in looping, so I can do: somefunction(data[counter].a, data[counter].b) — Joey Hipolito
– Joey Hipolito, Commented Apr 5, 2014 at 14:52

Andy · Accepted Answer · 2014-04-05 14:57:51Z

1

This will give you a syntax error (SyntaxError: missing ] after element list):

var data = [300: {a:"some", b:"value"}, 301: {a: "another", b: "val"}];

You mean this:

var data = {300: {a:"some", b:"value"}, 301: {a: "another", b: "val"}};

And to convert that into an array, loop over the object and push each value into a new array:

var arr = [];
for (var k in data) {
  arr.push(data[k]);
}

Fiddle

answered Apr 5, 2014 at 14:57

Andy

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1 Comment

Joey Hipolito Over a year ago

actually when I looked at the retured object of my code, yeah, it's not in the [], it's in {}, dunno why I thought it was in []

jonasnas · Accepted Answer · 2014-04-05 15:05:33Z

1

If you meant that the initial structure of array is this:

var data = [{300: {a:"some", b:"value"}}, {301: {a: "another", b: "val"}}];

then this should work (result array):

var result = [];
var data = [{300: {a:"some", b:"value"}}, {301: {a: "another", b: "val"}}];
for(var i =0; i < data.length; i++){
    for(var key in data[i]) {
        if(data[i].hasOwnProperty(key)) {
            result.push(data[i][key]);
            break;
        }
    }
}

answered Apr 5, 2014 at 15:05

jonasnas

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Comments

Mehran Hatami · Accepted Answer · 2014-04-05 15:09:56Z

There is a point here that should be clarified. When you have a Array object which its values starts from 300 as its indexes, it means you have 300 indexes with undefined values, but if it is just an Array-like object it could be totally different.

Let's say this is not an Array-like and is an actual Array, so you have to filter it so that all the undefined values get removed from your array, so your array should be like:

var arr = [/*0*/undefined, ..,/*299*/undefined, /*300*/{a:"some", b:"value"}, /*301*/ {a: "another", b: "val"} ...]
var result = arr.filter(function(value,index){
    return (value !== undefined);
});

but what you have mentioned in your question, is more likely a javascript object, so to do what you want you can do:

var myObj = {300: {a:"some", b:"value"}, 301: {a: "another", b: "val"} };
var result = {};
for(var key in obj){
    if(obj.hasOwnProperty(key)){
        result.push(obj[key]);
    }
}

in this for loop hasOwnProperty function helps you make sure if it is one of the actual object values, and not other possible keys from the object's prototype chain.

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