Hash#transform_values

hash_transform_values.rb

class Hash
  def transform_values(recursive = true, &block)
    Hash[
      map do |k, v|
        [
          k,
          (v.is_a?(Hash) && recursive) ? v.transform_values(&block) : yield(v)
        ]
      end
    ]
  end

  def transform_values!(recursive = true, &block)
    each do |k, v|
      self[k] = (v.is_a?(Hash) && recursive) ? v.transform_values(&block) : yield(v)
    end
  end
end

r = {:a => 1, :b => {:c => 2}}.freeze
puts r.transform_values {|val| val + 1}.inspect
#=> {:a => 2, :b => {:c => 3}}

h = {:a => 1, :b => {:c => 2}}

h.transform_values! {|val| val + 1}
puts h.inspect