Question

I have a nested hash:

hash = {
  "a" => "a",
  "b" => {
    "c" => "c",
    "d" => {
      "e" => "e"
    }
  }
}

and I have a hash:

new_value = {
  "b.d.e" => "new value"
}

I need some sort of “magical” function that replaces the value of the hash at hash["b"]["d"]["e"], like:

magical_function(hash, new_value)
#=> hash = {
      "a" => "a",
      "b" => {
        "c" => "c",
        "d" => {
          "e" => "new value"
        }
      }
    }

I have no idea how. Can someone help please?

Answer 1

Here’s another solution:

class Hash
  def replace_value(*keys, value)
    current = self
    current = current[keys.shift] while keys.size > 1
    current[keys.last] = value
  end
end

Called by invoking hash.replace_value("b","d","e", "new_value").