Ruby Hash deep_set

ruby_hash_deep_set.rb

Hash.class_eval do
  
  def deep_set(keys_array, val)
    keys_array[0...-1].inject(self){|result, key| 
      if !result[key].is_a?(Hash)
        result[key] = {}
      end

      result[key]
    }.send(:[]=, keys_array.last, val)

    return self
  end
  
end


h = {}
h.deep_set([:foo, :bar, :asd], "foobar")
h # => { foo: { bar: { asd: "foobar" } } }

without_monkey_patch.rb

class Helper  
  
  def self.deep_set(hash, keys_array, val)
    if !hash.is_a?(::Hash)
      raise TypeError.new("Invalid object passed to #{__method__}, must be a Hash")
    end
    
    keys_array[0...-1].inject(hash){|result, key| 
      if !result[key].is_a?(Hash)
        result[key] = {}
      end

      result[key]
    }.send(:[]=, keys_array.last, val)

    return hash
  end
  
end


h = {}
Helper.hash_deep_set(h, [:foo, :bar, :asd], "foobar")
h # => { foo: { bar: { asd: "foobar" } } }