code optimization

if params[:a].nil?
  if params[:b].nil?
       "999"
  else
     params[:b]
  end
else
  params[:a]
end

the same can be written using ternary operator

@a1 = params[:a].nil? ? params[:b].nil? ? ‘999′ : params[:b] :params[:a]

But you know RoR is so powerful…..
@a1 = params[:a] ||= params[:b] ||= ‘999′
[Background support : Ashish S.]