Deep merge hashes

deep_merge.rb

def deep_merge(h1, h2)
  h1.merge(h2) { |key, h1_elem, h2_elem| deep_merge(h1_elem, h2_elem) }
end

# Usage
wish_list = {
  8 => {
    title: "The Color of Magic",
  },
  42 => {
    title: "The Hitch-Hiker's Guide to the Galaxy",
    price: 5
  }
}
basket = {
  8 => {
    price: 10
  },
  1729 => {
    title: "Ramanujan:  Twelve Lectures on Subjects Suggested by His Life and Work",
    price: 28
  }
}

deep_merge(basket, wish_list)