rails select tag with multiple values pre selected

Question

I am trying to have a multiple select box. select box will contain all the stores in the DB but the ones that the user belongs to will be selected.

I\'m half way

Answer 1

after a fair amount of trial and error the following worked for me:

<%= select_tag 'stores[]', options_for_select(@stores.map { |s| [s.store_name, s.store_id] }, @user.stores.pluck(:id)), multiple: true, size: 10 %>

Answer 2

Another way of doing this would be to use the options_from_collection_for_select helper method. It will look something like this:

<%= select_tag 'stores[]', options_from_collection_for_select(@stores, :store_id, :store_name, [4,5,6]), multiple: true, size: '10%' %>