From Newsgroup: comp.lang.lisp

Erik Naggum wrote:

The obvious implementation of INTERSECTION is the trivial

(defun intersection (list-1 list-2-not)
(loop for elt in list-1
if (member elt list-2)
collect elt))

Obvious only to one who would rather program in COBOL than in
a Lispy language.

Gauche Scheme

"We don't need no stinkin' loops!"

(define (intersection list-1 list-2)
(filter (cut member <> list-2) list-1))

(intersection (iota 22) '(-3 2 8 9 88))

(2 8 9)
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