eharetea

Filters a sequence based on a predicate.

Filters a sequence based on a predicate.

Date Created:Friday October 03rd, 2008 08:09 PM
Date Modified:Friday October 03rd, 2008 08:22 PM

#|
filter maps over a sequence and keeps only the elements
that the predicate tests and returns true on. 
|#

(define (filter predicate seq)
    (cond ((null? seq) '())
          ((predicate (car seq)) (cons (car seq) (filter predicate (cdr seq))))
          (else (filter predicate (cdr seq)))))


(define test
(filter (lambda (x) (= (modulo x 2) 0)) (list 1 2 3 4 5 6))
)

Filter procedure by Dan Lynch
is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License
Based on a work at www.3daet.com
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