enumerable_extensions.rb

class Enumerable
  # Like map/collect, but generates a Hash. 
  # The block is expected to return two values: the key and the value for the new hash.
  def graph(&yld)
    inject({}) do |h, *kv|
      r = *yld[*kv]        
      nk, nv = *r          
      h[nk] = nv
      h
    end
  end
end

ZippyHash.rb

def build_message
  message = PORTFOLIO_FIELDS.graph{|field, _| [field, send(field)] }
  self.message = message.delete_if { |_, value| value.nil? }
end