Question

I have a hash that I’m getting from using JSON.parse. I am inserting into db at that point. The data structure uses acts as tree so I can have a hash like this:

category_attributes
  name: "Gardening"
  items_attributes:
    item 1: "backhoe"
    item 2: "whellbarrel"
  children_attributes
    name: "seeds"
    items_attributes
      item 3: "various flower seeds"
      item 4: "various tree seeds"
    children_attributes
      name: "agricultural seeds"
      items_attributes
        item 5: "corn"
        item 6: "wheat"

For this hash, I’d like to return an array of all the items_attributes. I have seen this question Traversing a Hash Recursively in Ruby but it seems different. Is there a way to recursively search a hash and return all those elements? Ideally, empty items_attributes should come back with nothing rather than nil.

thx

Answer 1

You can do something like this:

def collect_item_attributes h
  result = {}
  h.each do |k, v|
    if k == 'items_attributes'
      h[k].each {|k, v| result[k] = v } # <= tweak here    
    elsif v.is_a? Hash
      collect_item_attributes(h[k]).each do |k, v|
        result[k] = v
      end
    end
  end
  result
end

puts collect_item_attributes(h)
# => {"item 1"=>"backhoe", 
# "item 2"=>"whellbarrel", 
# "item 3"=>"various flower seeds", 
# "item 4"=>"various tree seeds", 
# "item 5"=>"corn", 
# "item 6"=>"wheat"}