Path: utzoo!mnetor!uunet!husc6!think!barmar
From: barmar@think.COM (Barry Margolin)
Newsgroups: comp.lang.lisp
Subject: Re: Filtering Vectors in CL Question
Message-ID: <13979@think.UUCP>
Date: 18 Dec 87 21:06:59 GMT
References: <1350001@otter.HP.COM>
Sender: usenet@think.UUCP
Reply-To: barmar@sauron.think.com.UUCP (Barry Margolin)
Organization: Thinking Machines Corporation, Cambridge, MA
Lines: 18

In article <1350001@otter.HP.COM> kers@otter.HP.COM (Christopher Dollin) writes:
>What is the idiomatic and efficent way in CL to filter a vector; that is, to
>make a new vector from an existing vector, containing only those elements
>that satisfy some patameter predicate, and preserving the order?

(defun filterv (v p)
  (delete-if-not p v))

The second argument of DELETE-IF-NOT is actually a sequence, which
encompasses lists and vectors, and the result is a sequence of the
same type as the input.

---
Barry Margolin
Thinking Machines Corp.

barmar@think.com
seismo!think!barmar