A little Clojure function to filter a list by some predicate and divide it into those elements for which the predicate is true and those elements for which the predicate is not true.

gistfile1.clj

(defn filter-by [pred coll]
  (let [grouped-map (group-by pred coll)
        {true-list true
         false-list false} grouped-map]
    (merge [true-list false-list])))

(= '[[1 3 5 7 9] [0 2 4 6 8]] (filter-by odd? (range 10)))