Best way to convert strings to symbols in hash

Question

What\'s the (fastest/cleanest/straightforward) way to convert all keys in a hash from strings to symbols in Ruby?

This would be handy when parsing YAML.

Answer 1

This is not exactly a one-liner, but it turns all string keys into symbols, also the nested ones:

def recursive_symbolize_keys(my_hash)
  case my_hash
  when Hash
    Hash[
      my_hash.map do |key, value|
        [ key.respond_to?(:to_sym) ? key.to_sym : key, recursive_symbolize_keys(value) ]
      end
    ]
  when Enumerable
    my_hash.map { |value| recursive_symbolize_keys(value) }
  else
    my_hash
  end
end