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

Here's a way to deep symbolize an object

def symbolize(obj)
    return obj.inject({}){|memo,(k,v)| memo[k.to_sym] =  symbolize(v); memo} if obj.is_a? Hash
    return obj.inject([]){|memo,v    | memo           << symbolize(v); memo} if obj.is_a? Array
    return obj
end

Answer 2

If you would like vanilla ruby solution and as me do not have access to ActiveSupport here is deep symbolize solution (very similar to previous ones)

    def deep_convert(element)
      return element.collect { |e| deep_convert(e) } if element.is_a?(Array)
      return element.inject({}) { |sh,(k,v)| sh[k.to_sym] = deep_convert(v); sh } if element.is_a?(Hash)
      element
    end

Answer 3

A modification to @igorsales answer

class Object
  def deep_symbolize_keys
    return self.inject({}){|memo,(k,v)| memo[k.to_sym] = v.deep_symbolize_keys; memo} if self.is_a? Hash
    return self.inject([]){|memo,v    | memo           << v.deep_symbolize_keys; memo} if self.is_a? Array
    return self
  end
end

Answer 4

So many answers here, but the one method rails function is hash.symbolize_keys

Answer 5

Here's a better method, if you're using Rails:

params.symbolize_keys

The end.

If you're not, just rip off their code (it's also in the link):

myhash.keys.each do |key|
  myhash[(key.to_sym rescue key) || key] = myhash.delete(key)
end

Answer 6

http://api.rubyonrails.org/classes/Hash.html#method-i-symbolize_keys

hash = { 'name' => 'Rob', 'age' => '28' }
hash.symbolize_keys
# => { name: "Rob", age: "28" }