flatten_dictionary.rb

def flatten(dict)
   output_dict = {}
   dict.each do |k,v|
      if v.is_a? Hash
         sub_dict = flatten(v)
         sub_dict.each do |sk, sv|
            output_dict[k+'.'+sk] = sv
         end
      else
         output_dict[k] = v
      end
   end
   output_dict
end

# input = {
#  'Key1' => '1',
#  'Key2' => {
#     'a' => '2',
#     'b' => '3',
#     'c' => {
#       'd' => '3',
#       'e' => '1'
#       }
#     }
# }

# output = {
#  'Key1' => '1',
#  'Key2.a' => '2',
#  'Key2.b' => '3',
#  'Key2.c.d' => '3',
#  'Key2.c.e' => '1'
# }