University
of Washington • CSE583 • D. Notkin © 2000
42
map:
apply a function to each element of a list, returning a list
l(map square ‘(3 4 5)) ® (9 16 25)
l(map
is-positive? ‘(3 -4 5)) ® (#t #f #t)
l(defun (map
fn x)
(if (null? x) ()
(cons (fn (car x))
(map fn (cdr x)))))
(if (null? x) ()
(cons (fn (car x))
(map fn (cdr x)))))
lThe
resulting list is always of the same length as the list to which map is applied