SIFT (new utility) - Separate the wheat from the chaff.

[heegaiximephoomeeghahyaiseekh]

(defun sift (predicate list)
   "Returns two values from the LIST: A list of values that satisfy the PREDICATE,
and a list of those that don't."
   (loop for item in list
        if (funcall predicate item) collect item into gold
        else collect item into dirt
       finally (return (values gold dirt))))

Provides: sift Requires: Nothing Author: Jeremy Phelps License: Public Domain

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Hello! Thanks for the submission. Have you seen partition-if?

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I'm going to close. Please re-open if I missed something!