Question

I currently have a Order and image model which look like this:

class Order < ActiveRecord::Base
  has_many :images
end

class Image < ActiveRecord::Base
  belongs_to :order
end

Now i’d like to do the following:

<% @order.images.each do |image| %>
  <%= image.format %> x  
  <%= image.amount %>
  <%= number_to_currency(image.price) %><br/>
<% end %>

This prints out this:

1x 30x30 € 1,00
1x 12x12 € 2,10
3x 30x30 € 3,00
4x 12x12 € 8,40

I’d like to combine this by image format, and sum the amount and price. But I’ve tried several methods but none seem to work because the @order.images isn’t a simple array but an Image object. This is what I would like to achieve:

5x 12x12 € 10,50    
4x 30x30 € 4,00

Answer 1

You could try using group_by:

@order.images.group_by(&:format).each do |format, images|
  <%= "#{images.length}x #{format} #{number_to_currency(images.sum(&:price))" %>
end

Should do the trick. images is an array of objects with equal values of format.