how to get selected text from a dropdown in rails

I have my options in an array

@groupings = [["Text 1", "value_1"],["Text 2", "value_2"]]

so im using a

select_tag(:groupby, options_for_select(@groupings, params[:groupby]))

I'd like to populate an H3 tag on the page with the selected text. (ie "Text 2" if params[:groupby ] = "value_2" )

Is there a rails way to do this? Other than manually deriving it from the @groupings array?

TIA, Kirby

Maybe all you need is a simple find call, and these are often best wrapped in a helper:

def label_for_grouping(group_id)
  grouping = @groupings.find { |g| g[1] == group_id }

  grouping and grouping[0]
end

Then later:

<h3><%= label_for_grouping(params[:groupby]) %></h3>

This look-up would be easier if you had a Hash version of your @groupings variable, or perhaps simply kept it as a Hash and rendered it as an Array using .to_a where required.