Z = X + Y时如何防止堆叠顺序？ X总是在最前面

Question

Here's what I mean

This is my controller

class StaticPagesController < ApplicationController

  def home
    if signed_in?
      @post_items = current_user.posts
      @activities = PublicActivity::Activity.order("created_at desc")
      @items = @post_items + @activities
      @items.sort_by{|item| item.class == PublicActivity::Activity ? item.created_at : item.created_at}
      @items = @items.paginate(:page => 1, :per_page => 20)
    else
    redirect_to root_path  
    end
  end

As you can see in the above, this line @items = @post_items + @activities causes stacked ordering. All of the post_items are ordered first THAN the activities are ordered below it.

I am trying to combine BOTH into one ordering using "created_at".

How can I prevent this stacked ordering and make it order as one? Thanks

Answer 1

sort_by isn't doing what you think it's doing. It's returning a new sorted array. If you want to modify the array in-place, you have to use sort_by! :

@items.sort_by!(&:created_at)