Count occurrences

Array#occurrences

class Array
  # Takes %(apple apple strawberry orange orange apple) and returns { apple: 3, orange: 2, strawberry: 1 }
  def occurrences
    r = {}
    group_by {|i| i}.each{|k,v| r[k] = v.count}
    sorted = {}
    r.sort_by {|k,v| -v}.each {|i| sorted[i[0]] = i[1] }
    sorted
  end
end