Question

Provided the following ruby hash:

{
    cat: {
        1: 2,
        2: 10,
        3: 11,
        4: 1
    },
    wings: {
        1: 3,
        2: 5,
        3: 7,
        4: 7
    },
    grimace: {
        1: 4,
        2: 5,
        3: 5,
        4: 1
    },
    stubborn: {
        1: 5,
        2: 3,
        3: 7,
        4: 5
    }
}

How can I sort the hash by the sum of ‘leaf’ excluding “4”, for instance the value to compare for “cat” would be (2 + 10 + 11) = 23, the value for “wings” would be (3 + 5 + 7) = 15 so if I was comparing just those two they would be in the correct order, highest sum on top.

It is safe to assume that it will ALWAYS be {1: value, 2: value, 3: value, 4: value} as those are keys for constants I have defined.

It is also safe to assume that I will only ever want to exclude the key “4”, and always use the keys “1”, “2”, and “3”

Based on Jordan’s suggestion I got this to work:

  tag_hash = tag_hash.sort_by do |h| 
    h[1].inject(0) do |sum, n| 
      n[0] == 4 ? sum : sum + (n[1] || 0)
    end
  end

The results seem a bit off but it appears to be my code, once I confirm that I’ll accept the answer, thanks Jordan!

I’ve updated my solution to use Wayne Conrad’s idea, see my comment on his answer – Is it possible that its not carrying everything when it sorts, I linked to an image in my comment that shows the result of the actual sort in graph form.. seems odd to me..

Answer 1

tag_hash = tag_hash.sort_by do |_, leaf|
  leaf.reject do |key, _|
    key == 4
  end.collect(&:last).inject(:+)
end