Q: The first zero elements of a list comprise what list?
A: The empty list. Q: The first n elements of a list is what list? (Hint: Answer in terms of the head and the tail.) A: The list created by consing the head onto the first n-1 elements of the tail. |
(define first-elements-of (lambda (n list) (if (= n 0) '() (cons (car list) (first-elements-of (- n 1) (cdr list)))))) |