Ruby: Get all keys in a hash (including sub keys)

Question

let\'s have this hash:

hash = {\"a\" => 1, \"b\" => {\"c\" => 3}}
hash.get_all_keys 
=> [\"a\", \"b\", \"c\"]

how can i get all key

Answer 1

class Hash

  def get_all_keys
    [].tap do |result|
      result << keys
      values.select { |v| v.respond_to?(:get_all_keys) }.each do |value| 
        result << value.get_all_keys
      end
    end.flatten
  end

end

hash = {"a" => 1, "b" => {"c" => 3}}
puts hash.get_all_keys.inspect # => ["a", "b", "c"]