Can I set a variable to a variable combination in javascript?

Question

Here's my code:

var album1 = "First Album name";
var album2 = "Second Album Name";
var album3 = "Third Album Name";
var album4 = "Fourth Album name";
var album5 = "Fifth Album name";

var currentAlbumCtr = 1;
var currentAlbum = album + currentAlbumCtr;

currentAlbum should be set to album1 if currentAlbumCtr is 1. Can anyone help?

Have a read here... http://www.w3schools.com/js/js_obj_array.asp — Mark Setchell, Apr 06 '14 at 22:34
You shall create an array of albums, so that you can get a specific index — xav, Apr 06 '14 at 22:34
and most of these: [`[javascript] dynamic variables`](https://stackoverflow.com/search?q=[javascript]+dynamic+variables). — Felix Kling, Apr 06 '14 at 22:59
@adeneo I think Bergi was right. It is an XY. In a real app, there would be a database of albums. The programmer would query it in code and probably receive back an array of objects. The OP should really be asking "how do I work with album data in a sustainable way?" rather than "how do I access a bunch of globals as if it were an organized array?" — Paul, Apr 06 '14 at 23:08

Stephen Thomas · Accepted Answer · 2014-04-06T22:41:59.240

3

You could use eval to achieve what you want, but that would probably be the wrong way to do it. Why not use an array:

var album = [];
album[1] = "First Album name";
album[2] = "Second Album Name";
album[3] = "Third Album Name";
album[4] = "Fourth Album name";
album[5] = "Fifth Album name";

currentAlbumCtr = 1;
currentAlbum = album[currentAlbumCtr];

Or, alternatively,

var album = {
    "1": "First Album name";
    "2": "Second Album Name";
    "3": "Third Album Name";
    "4": "Fourth Album name";
    "5": "Fifth Album name";
};

Or even

var album = [
    "First Album name",
    "Second Album Name",
    "Third Album Name",
    "Fourth Album name",
    "Fifth Album name"
];

currentAlbumCtr = 1;
currentAlbum = album[currentAlbumCtr-1];

Note the -1 on the last statement since arrays are normally indexed from 0

edited Apr 06 '14 at 22:41

answered Apr 06 '14 at 22:35

Stephen Thomas

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2

Your array indices are odd. Why not use an array literal? – Bergi Apr 06 '14 at 22:36
Closest to the OP's original code. There's nothing wrong with skipping an index. – Stephen Thomas Apr 06 '14 at 22:36
1

…apart from that `album.length` is `6`? – Bergi Apr 06 '14 at 22:37
@Bergi Only about half of his array indices are odd. There does seem to be a choice between array index/ description mismatch and proper array length. Usually the first concern loses because the user doesn't need to see the array indexes. – Paul Apr 06 '14 at 22:49
@Paul: I didn't mean "odd" as in "not even", but rather "strange". I'm not a native speaker :-/ How would you have phrased that? – Bergi Apr 06 '14 at 22:54
@Bergi Ah well, that word "odd" has both meanings so you did OK. You could have said "Why are you creating an array-like object with string indices instead of an array?" but what you said was fine. – Paul Apr 06 '14 at 22:58
Thanks - I feel dumb for not originally thinking to use an array... lazy sunday I guess. – teo751 Apr 06 '14 at 23:02

score 0 · Answer 2 · answered Apr 06 '14 at 22:36

0

currentAlbum should be set to album1 if currentAlbumCtr is 1.

if (currentAlbumCtr == 1) {
    currentAlbum = album1;
}

answered Apr 06 '14 at 22:36

user3504561

63
5

score 0 · Answer 3 · answered Apr 06 '14 at 22:43

0

Not exactly sure what you're asking for. Does this work?

script:

var albums =
           [ "album1",
             "album2",
             "album3" ];

$("#clickme").click(function(){
    var currentAlbum = parseInt($("#album_number").val()) % albums.length;
    alert(albums[currentAlbum]);
})

HTML:

<button id="clickme">click!</button>
<input id="album_number"></input>

answered Apr 06 '14 at 22:43

royhowie

11,075
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@Bergi Well, that was just for grabbing the input value. I wasn't sure bow the OP wanted to set it up. – royhowie Apr 07 '14 at 01:00

score -1 · Answer 4 · answered Apr 06 '14 at 22:35

-1

var currentAlbum = eval("album" + currentAlbumCtr);

answered Apr 06 '14 at 22:35

Taher

11,902
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That's why `eval` is evil. – Bergi Apr 06 '14 at 22:36
eval is not evil in this case, ps: that could do without -1, its a working solution still – Taher Apr 06 '14 at 22:39
2

No, this is exactly the case where [`eval` is a bad idea](http://stackoverflow.com/a/87260/1048572), and that's worth a downvote. Especially when introducing this to a learner: At some day he will learn what `eval` is good for, but he will need to understand arrays first. – Bergi Apr 06 '14 at 22:41
1

`currentAlbumCtr = ';document.write("Minimalism forever.")'` – Paul S. Apr 06 '14 at 22:45

Can I set a variable to a variable combination in javascript?

4 Answers4