/ Ruby on Rails
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method

deep_symbolize_keys

v4.0.2 - Show latest stable - Class: Hash
deep_symbolize_keys()
public

Return a new hash with all keys converted to symbols, as long as they respond to to_sym. This includes the keys from the root hash and from all nested hashes.

hash = { 'person' => { 'name' => 'Rob', 'age' => '28' } }

hash.deep_symbolize_keys
# => { person: { name: "Rob", age: "28" } }

1Note

Does not symbolize hashes in nested arrays

EdvardM ยท Apr 23, 2014

If you have a nested structure containing arrays of hashes, you still need to do that on your own, eg.

module SymbolizeHelper
  def symbolize_recursive(hash)
    {}.tap do |h|
      hash.each { |key, value| h[key.to_sym] = map_value(value) }
    end
  end
 
  def map_value(thing)
    case thing
    when Hash
      symbolize_recursive(thing)
    when Array
      thing.map { |v| map_value(v) }
    else
      thing
    end
  end
end

Or, if you want to get really fancy with Ruby refinements (YMMV), one could do

module SymbolizeHelper
  extend self

  def symbolize_recursive(hash)
    {}.tap do |h|
      hash.each { |key, value| h[key.to_sym] = transform(value) }
    end
  end

  private

  def transform(thing)
    case thing
    when Hash; symbolize_recursive(thing)
    when Array; thing.map { |v| transform(v) }
    else; thing
    end
  end

  refine Hash do
    def deep_symbolize_keys
      SymbolizeHelper.symbolize_recursive(self)
    end
  end
end

And later say

using SymbolizeHelper # augmented Hash#deep_symbolize_keys is now available