Can you do an :order in ruby after a find?

Question

Is it possible in ruby/rails to order a result set after doing a find? For example, is it possible to do something like this

Warning: Does not work

if type == 1
  @items = mycompany.items
else
  @items = myhome.items
end

@items = @items :order => "created_at"

I would assume something like this should be possible, but I'm still very new to RoR and can't seem to find anything on google.

Answer 1

You should be able to do one of these:

Sort when accessed:

if type == 1
  @items = mycompany.items(:order => 'created_at')
else
  @items = myhome.items(:order => 'created_at')
end

Sort after accessing:

@items.sort{|a,b| a.created_at <=> b.created_at}

Answer 2

You could also use the Symbol to Proc shorthand available in rails, along with Enumerable#sort_by to simplify your sort statement, if you want to sort after collecting ActiveRecord objects:

@items.sort_by(&:created_at)
# is the same as @items.sort{ |a, b| a.created_at <=> b.created_at }

Answer 3

I don't know why everyone's all "No you can't" when it's possible in named scopes.

For example, define as part of ActiveRecord::Base:

named_scope :by_created_at, :order_by => 'created_at'

This allows you to convert a simple relationship to an ordered one before it is actually retrieved:

@items = @items.by_created_at

As a note it's not a good idea to include scopes which have overlapping :order definitions as this causes them to be appended instead of over-riding each in turn.

However, in your example it's not too much of a stretch to imagine refactoring it as the following:

reference =
  case (type)
  when 1
     mycompany
  else
    myhome
  end

@items = reference.items.all(:order_by => 'created_at')