This method can iterate over a big diverse data-set and return the hash which matches the field value.

recursive_traversal.rb

 @fields = [{
   :foo => [
     1,
     2,
     [
       3,
       {:field => 'oranges', :options =>{ :label => "Oranges"}}
     ],
     {:a => {:zaz => 42}},
     [
      {:field => 'apples', :options => {:label => "Apples"}},
      {:field => 'bananas', :options => {:label => "Bananas"}}
     ]
   ]
 }]
 
def find_nested_hash_by_key_value(node, key, search_for)
  if node.respond_to?(:key?) && node.key?(key)
    if node[key] == search_for
      node
    end
  elsif node.respond_to?(:each)
    r = nil
    node.find{ |*a| r=find_nested_hash_by_key_value(a.last,key,search_for) }
    r
  end
end
 
search_for = "apples"
puts find_nested_hash_by_key_value(@fields, :field, search_for)
## => {:field => 'apples', :options => {:label => "Apples"}}