Question

I have a ruby hash that looks like this

{ 'stuff_attributes' => {      '1' => {'foo' => 'bar', 'baz' => 'quux'},       '2' => {'foo' => 'bar', 'baz' => 'quux'}     } } 

and I want to turn it into a hash that looks like this

{ 'stuff_attributes' => [     { 'foo' => 'bar', 'baz' => 'quux'},     { 'foo' => 'bar', 'baz' => 'quux'}   ] } 

I also need to preserve the numerical order of the keys, and there is a variable number of keys. The above is super-simplified, but I’ve included a real example at the bottom. What’s the best way to do this?

P.S

It also needs to be recursive

As far as the recursion goes, here’s what we can assume:

1) the key that needs to be manipulated will match /_attributes$/ 2) the hash will have many other keys that do not match /_attributes$/ 3) the keys inside the hash will always be a number 4) an _attributes hash can be at any level of the hash under any other key

this hash is actually the params hash from a create action in the controller. This is a real example of what will need to be parsed with this routine.

{     'commit'=>'Save',      'tdsheet'=>{     'team_id'=>'43',      'title'=>'',      'performing_org_id'=>'10',      'tdsinitneed_attributes'=>{          '0'=>{             'title'=>'',              'need_date'=>'',              'description'=>'',              'expected_providing_organization_id'=>'41'             },          '1'=>{             'title'=>'',              'need_date'=>'',              'description'=>'',              'expected_providing_organization_id'=>'41'             }         },          'level_two_studycollection_id'=>'27',          'plan_attributes'=>{             '0'=>{                 'start_date'=>'', 'end_date'=>''             }         },          'dataitem_attributes'=>{             '0'=>{                 'title'=>'',                  'description'=>'',                  'plan_attributes'=>{                     '0'=>{                         'start_date'=>'',                          'end_date'=>''                         }                     }                 },              '1'=>{                 'title'=>'',                  'description'=>'',                  'plan_attributes'=>{                     '0'=>{                         'start_date'=>'',                          'end_date'=>''                         }                     }                 }             }         },      'action'=>'create',      'studycollection_level'=>'',      'controller'=>'tdsheets' } 

Answer 1

Note that this might be long to test if all keys are numbers before converting…

def array_from_hash(h)   return h unless h.is_a? Hash    all_numbers = h.keys.all? { |k| k.to_i.to_s == k }   if all_numbers     h.keys.sort_by{ |k| k.to_i }.map{ |i| array_from_hash(h[i]) }   else     h.each do |k, v|       h[k] = array_from_hash(v)     end   end end