P03 - Find the nᵗʰ Element of a List

This problem is very nice because the Clojure and Scala implementations are practically the same. It allows to appreciate the different syntaxes better.

Below is Peter’s solution to the problem, in Clojure:

(defn kth [n xs]  
  {:doc "P03 (*) Find the Kth element of a list." 
   :pre [(seq? xs)]}
  (if (= 0 n)
    (first xs)
    (recur (- n 1) (next xs)))
  )

Here is my Scala:

def nth[T](n: Int, list: List[T]): T =
  if (n == 0)
    list.head
  else
    nth(n - 1, list.tail)

In this case one can see a small but significant difference where Clojure sticks to functional-programming and Scala favours object-oriented: while in Clojure first and next are functions that operate on collections, in Scala head and tail are methods to be called upon a collection instance.