(defn myswap [l Dl]
 (let [unique-l (uc (to-vect Dl))
    swap-l (fn [item]
         (let [new-unique-l (remove #(= % item) unique-l)
            new-item  (if (= (count new-unique-l) 1)
                  (first new-unique-l)
                  (first (shuffle new-unique-l)))]
          new-item))]
   (matrix (map #(swap-l %) l))))

(defn swap-class [D]
 (let [att (sel D :cols (range 0 (- (ncol D) 1)))
    klass (sel D :cols (- (ncol D) 1))
    klass10 (matrix (take (* 0.1 (nrow klass)) klass))
    klass90 (matrix (drop (* 0.1 (nrow klass)) klass))
    klass-new (bind-rows (myswap klass10 klass) klass90)]
   (bind-columns att klass-new)))