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Re: Wanted: mapcar() without nils
From: |
Nordlöw |
Subject: |
Re: Wanted: mapcar() without nils |
Date: |
Sat, 13 Jun 2009 12:45:06 -0700 (PDT) |
User-agent: |
G2/1.0 |
Oopps, my mistake got a parenthesis wrong...
Now it works:
(defun extract-elements (pred seq)
"Extract a copy of SEQ containing all elements fullfilling
PRED."
(delq nil (mapcar `(lambda (elm) (when (,pred elm) elm)) seq)))
;; Use: (extract-elements 'symbolp '(a b 1 2)) => '(a b)
;; Use: (extract-elements 'numberp '(a b 1 2)) => '(1 2)
Thanks,
Nordlöw