Dan's Thoughts Thinking somewhat carefully

Exercise 2.17 of SICP

Exercise 2.17: Define a procedure last-pair that returns the list that contains only the last element of a given (nonempty) list:

(last-pair (list 23 72 149 34))
(34)

(define (last-pair ls)
  (let ((last-pair-index (- (length ls) 1)))
    (list-ref ls last-pair-index)))

> (last-pair (list 1 2 3 4 5))
5