Question

def valueize(val)
  # randomly returns nil or random integer ([-100 to +100] + val)
  ((rand(100) % 3) == 0) ? nil : (rand(200)-100+val)
end

hash = {
  x: 11,
  y: 22,
  z: 33
 }

sort_by_abs = hash.sort_by{ |k, v|  (valueize(v)).abs }
sort_by_min = hash.sort_by{ |k, v|  (valueize(v))     }
sort_by_max = hash.sort_by{ |k, v| -(valueize(v))     }

What is the most rubyish way of ensuring nil results are always sorted to the bottom, for each of the three sorts?

Conditions:

• Range of potential hash values is unknown (hash values will always be integers)
• valueize method cannot be modified
• sort blocks can be modified

Answer 1

A simple approach (using ick’s maybe just to keep it compact, do an assignment + conditional if you feel more confortable with it):

inf = Float::INFINITY
sort_by_abs = hash.sort_by { |k, v| valueize(v).maybe.abs || inf }
sort_by_min = hash.sort_by { |k, v| valueize(v) || inf }
sort_by_max = hash.sort_by { |k, v| valueize(v).maybe.send(:-@) || inf }