How to select element by id within existing selection?

Question

Given HTML:

<div id="div-a"></div>
<div id="div-b"></div>
<div id="div-c"></div>

And a previously-created jQuery selection:

var $divs = $("div");

How can I select a particular div in that selection by its id?
Note: the $divs selection has not yet been appended to the DOM, so I can't just select directly (e.g. $("#div-b")).

find() selects descendants of a selection, so this does not work:

$divs.find("#div-b");

has() / :has() selects elements that contain an element with the specified selector, so this does not work:

$divs.has("#div-b");

Answer 1

If you want to only examine elements within a particular jQuery object that you've already created, you can use the .filter() method:

var $divs = $("div");
var item = $divs.filter("#div-a");

This will examine only the elements within the $divs jQuery object so see if any of them match the selector "#div-a" and will return to you a new jQuery object that contains only the matches (either zero or one object in this case).

Answer 2

I think you are looking for filter():

var $subset = $divs.filter("#div-b");

Answer 3

You want to use filter() to reduce the set/.

var elem = $divs.filter("#div-b");