ruby on rails - Iterate over has_many through relationship and include data from joining table -

i have simple rails app 3 models: recipes, ingredients, , joining table quantities stores amount of each ingredient in recipe. 1 recipe, want list associate ingredients , amount found in joining table. how iterate on ingredients, include data quantities table?

class recipe < activerecord::base      has_many :quantities     has_many :ingredients, through: :quantities     accepts_nested_attributes_for :quantities, :reject_if => :all_blank, :allow_destroy => true end 

and:

class ingredient < activerecord::base      has_many :quantities     has_many :recipes, through: :quantities end 

and joining table:

class quantity < activerecord::base     belongs_to :recipe     belongs_to :ingredient     accepts_nested_attributes_for :ingredient, allow_destroy: true end 

it seems should easy iteration not sure how.

show.html.erb:

<% @recipe.ingredients.each |ingredient| %>     <% #i know line below wrong, not sure how     # iterate on ingredients recipe ,     # include amount field quantities table     # ingredient name. %>     <li><%= ingredient.amount ingredient.name  %></li> <% end %> 

thank you!

in controller's action this:

@recipe = recipe.includes(:ingredients, :quantities).find(params[:id]) # avoid n+1 

and then, in view:

<% @recipe.quantities.each |quantity| %>   <%= quantity.ingredient.name %> -    <%= quantity.amount %> <% end %>