Re: Wanted: mapcar() without nils

[Lennart Borgman]

You misplaced a closing paren in the lambda

On Sat, Jun 13, 2009 at 8:24 PM, Nordlöw<per.nordlow@gmail.com> wrote:
> (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)))

 (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)