ruby - Sort a collection of objects by number (highest first) then by letter (alphabetical)

Question

I'm building a widget to show medal counts for the Olympics. I have a collection of "country" objects, where each has a "name" attribute, and "gold", "silver", "bronze" for medal counts.

List should be sorted: 1. First by total medal count 2. If same medals, sub-sort by type (gold > silver > bronze, ie. two golds > 1 gold + 1 silver) 3. If same medals and type, sub-sort alphabetically

I'm doing this in ruby, but I suppose the language doesn't matter. I did figure out a solution, but if feels like there must be a much more elegant way to do it.

Here's what I did:

1. Create a virtual attribute with the weighted medal total. So if they had 2 gold and 1 silver, weighted total would be "3.020100". 1 gold and 1 silver and 1 bronze would be "3.010101"

2. Since we want to sort the medal count as highest first, list is sorted DESC. But then we want to sub-sort alphabetically (ie. ASC) after that. So I created a function which would alpha-invert a word (ie. "canada" => "xzmzwz")

3. Convert the weighted total to a string, concat the reversed name (ie. "3010101xzmzwz"), then sort descending. Voila.

By now, someone has figured out how to do the same thing in about 2 lines of code. Care to enlighten me?

Answer 1

countries.sort_by do |country|
  medals = country.gold + country.silver + country.bronze
  [-medals, -country.gold, -country.silver, country.name]
end