Most Efficient Way to Sort By String, Based on Defined Array in Ruby on Rails

Question

I am trying to find the most efficient way to sort an array based on a defined order from another array and display it in my presenter. There is a property of the array that needs sorting, that I want to sort on, 'name'. So there is a function, 'dogs_available' that returns a collection of objects that looks like:

[{name:'Timmy', size:'small', eyes:'brown'},{name:'Rico', size:'large', eyes:'purple'}]

So I want

sort_order = ['Timmy', 'Charlie', 'Rico', 'Hannah']
m.dogs_available.sort do |x,y|
  x = sort_order.index x.name
  y = sort_order.index y.name
  if x.nil?
    -1
  elsif y.nil?
    -1
  else
    x <=> y
  end
end

And then to print it out (just for testing, I'll clean it up later) it looks like:

dogs = m.dogs_available
text = ""
dogs.each do |dog|
  text += "<h4>#{dog.name}</h4>"
end
text.html_safe

For starters, this sort doesn't work. Also, I am confident this isn't the best way to sort/compare. Any pointers?

Answer 1

Your existing sort logic can be replaced with

m.dogs_available.sort_by{|hash| sort_order.index(hash[:name]) || -1}

however, where is dogs_available coming from? Usually in rails you'd be pulling data out of the database, and you can do your sorting then.