what's the best way to convert a ruby hash to an array

Question

Hi All,

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

If we can assume that all the keys are in fact strings which convert cleanly to integers, the following ought to work:

# "hash" here refers to the main hash in your example, since you didn't name it
stuff_hash = hash["stuff"]
hash["stuff"] = stuff_hash.keys.sort_by {|key| key.to_i}.map {|key| stuff_hash[key]}

Answer 2

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