Turn an acts_as_tree structure into a select drop-down.
This is probably the easiest way to turn Rails’ acts_as_tree structure into a select field: HTML: <select name="category_id"> <%= expand_tree_into_select_field(Category.top) %> </select> Ruby helper: def expand_tree_into_select_field(categories) returning(String.new) do |html| categories.each do |category| html << %{<option value="#{ category.id }">#{ ‘ ’ * category.ancestors.size }#{ category.name }</option>} html << expand_tree_into_select_field(category.children) if category.has_children? end end end The Category.top method [...]