Customizing the text in a collection_select dropdown

Question

I have a collection_select dropdown that has a dropdown of names like this:

<%= f.collection_select(:person_id, Person.all, :id, :name) %>

But I have a foreign key on a person that points to a group they are part of. In the dropdown I want to show the persons name and the group next to them like this:

Paul (Golfers) Kevin (Sailors)

etc ...

Is this possible using the collection_select?

Answer 1

This is actually pretty simple to do. You just need to write a method on the model you're pulling from that formats the string that you want in the dropdown. So, from the documentation:

class Post < ActiveRecord::Base
  belongs_to :author
end

class Author < ActiveRecord::Base
  has_many :posts

  def name_with_initial
    "#{first_name.first}. #{last_name}"
  end
end

Then, in your collection_select just call that method instead of calling the name, or whatever you had show up before.

collection_select(:post, :author_id, Author.all, :id, :name_with_initial)

Seems pretty obvious in hindsight.