Something missing from jQuery?

Getting somewhat spoiled with Ruby, I was surprised jQuery didn’t have a function akin to Ruby’s sample. Of course it’s easy enough to implement on your own, but why not include it in the library?

$.fn.random = function() {
  var ret;
  ret = $();
  if (this.length > 0) {
    ret = ret.add(this[Math.floor(Math.random() * this.length)]);
  }
  return ret;
};

or if you prefer coffeescript:

$.fn.random = ->
  ret = $()
  if @length > 0
    ret = ret.add(@[Math.floor(Math.random() * @length)])
  ret

My usecase for this was something like the following: I have many accordions with collapsed panels, and I want one random panel in every accordion to be expanded.

$('[id^="accordion"]').find('.panel-collapse').random().addClass('in')