class Hash
  def stringify
    inject({}) do |options, (key, value)|
      options[key.to_s] = value.to_s
      options
    end
  end

  def stringify!
    each do |key, value|
      delete(key)
      store(key.to_s, value.to_s)
    end
  end
end

class Hash
  def except(*blacklist)
    reject {|key, value| blacklist.include?(key) }
  end

  def only(*whitelist)
    reject {|key, value| !whitelist.include?(key) }
  end
end

Struct to Hash:

class Struct
  def to_hash
    Hash[*members.zip(values).flatten]
  end
end

Hash to Struct:

class Hash
  def to_struct(name)
    Struct.new(name, *keys).new(*values)
  end
end

Ruby 1.8 doesn't retain the order of objects inserted in to a hash, but with ActiveSupport::OrderedHash you can do this:

a=ActiveSupport::OrderedHash[:one, 1, :two, 2]

which gives you:

=> #<OrderedHash {:one=>1, :two=>2}>

$ gem install hashery

require 'hashery/open_cascade'

data = {
  dog: {
     poop: true, {
        brain: {
           size: :average
        }
     }
  }
}
dog = Hashery::OpenCascade[data]
dog.poop => true
dog.brain.size => average

hashery