Remove element from list


You have a list and want to remove elements that return true for a given predicate procedure.


(define (remove fn lst)
  (let loop ((lst lst) (result '()))
    (if (null? lst)
        (reverse result)
        (let ((item (car lst)))
          (loop (cdr lst)
                (if (fn item) result (cons item result)))))))

Credit: Jakub T. Jankiewicz

Using SRFI

SRFI 1 has a remove procedure that works as above. It also has a filter procedure that is the opposite: if the predicate returns true the element will be kept in the resulting list.


(define >10 (lambda (x) (> x 10)))

(remove >10 '(1 2 3 4 10 11 12 13 14))
;; ==> (1 2 3 4 10)

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