From Newsgroup: comp.lang.lisp

B. Pym wrote:

Well if you alway use these two functions together, it would be more >> efficient to generate both the results at once:

...

The case could be made either way for this one, though, and certainly it would be better in terms of efficiency; thanks again for the suggestion.

...

(defun split-on-corpus (atoms preprocessed-corpus)
(loop :for atom :in atoms
:if (gethash atom preprocessed-corpus)
:collect atom :into present
:else :collect atom :into absent
:finally (return (list present absent))))

Gauche Scheme

(define table
(alist->hash-table '((foo . 2)(bar . 4)(j . 5)(k . 3))))

(define (split-on-corpus atoms corpus)
;; "!" is similar to "do".
(! (atom :in atoms
present cons atom
absent cons atom
:if-else (hash-table-exists? corpus atom))
#f @@ (list present absent)))


(split-on-corpus '(wow foo and bar or j is k) table)

===>
((foo bar j k) (wow and or is))
--
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