ruby how to read hash

Question

Controller code:

def index
  @folders = Folder.where(parent_id: 0, user_id: current_user)
  @subfolders = Hash.new()
  @folders.each_with_index do |folder, index|
    @subfolders[folder.id] = { folder.id => Folder.where(parent_id: folder.id) }
  end
end

View:

<% @folders.each_with_index do |folder, index| %>
  <td><%= folder.name %></td><br />
  @subfolders[index].name
<% end %>

the @subfolders[1].to_s object itself returns this result:

{1=>#<ActiveRecord::Relation [#<Folder id: 2, name: "tt", user_id: 1, created_at: "2014-06-21 19:29:32", updated_at: "2014-06-21 19:29:32", parent_id: 1>]>}

My question is , how to read this @subfolders Hash in view ? I want to display subfolder after parent is displayed... Please help

I think `@subfolders[folder.id]` will be `@subfolders[index]` Right ? — Arup Rakshit, Jul 07 '14 at 17:12
`@subfolders[folder.id][folder.id]` will do. but why you need such strange chaining. — maximus ツ, Jul 07 '14 at 17:22
Yes, thats working, but you right actually. The thing is, once i read all the parent folders, i need collection to store its subfolders, thats why i decided to use hases. If you have any suggestions please let me know? Is it possible to rewrite using arrays ? — user3581552, Jul 07 '14 at 17:29

score 1 · Accepted Answer · edited May 23 '17 at 12:11

1

The below is seems to be a more efficient solution to your problem as it runs 2 queries while yours generates an n + 1

ids = Folder.where(parent_id: 0, user_id: current_user).pluck(:id)
@subfolders = Folder.where(parent_id: ids).group_by(:parent_id)

edited May 23 '17 at 12:11

Community

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answered Jul 07 '14 at 17:40

bjhaid

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ruby how to read hash

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