diff --git a/src/clj_ml/data.clj b/src/clj_ml/data.clj
index 99619cd..a028a65 100644
--- a/src/clj_ml/data.clj
+++ b/src/clj_ml/data.clj
@@ -245,7 +245,7 @@
 
 (defn instance-value-at
   "Returns the value of an instance attribute"
-  [instance pos]
+  [^Instance instance pos]
   (let [attr (.attribute instance pos)]
     (if (.isNominal attr)
       (let [val (.value instance pos)
@@ -260,26 +260,16 @@
 
 (defn instance-to-vector
   "Builds a vector with the values of the instance"
-  [instance]
-  (let [max (.numValues instance)]
-    (loop [c 0
-           acum []]
-      (if (= c max)
-        acum
-        (recur (+ c 1)
-               (conj acum (instance-value-at instance c)))))))
+  [^Instance instance]
+  (vec (map (partial instance-value-at instance) (range (.numValues instance)))))
 
 (defn instance-to-map
   "Builds a vector with the values of the instance"
-  [instance]
-  (let [max (.numValues instance)]
-    (loop [c 0
-           acum {}]
-      (if (= c max)
-        acum
-        (recur (+ c 1)
-               (conj acum {(keyword (. (.attribute instance c) name))
-                           (instance-value-at instance c)} ))))))
+  [^Instance instance]
+  (reduce (fn [m i]
+            (assoc m (keyword (attribute-name-at instance i)) (instance-value-at instance i)))
+          {}
+          (range (.numValues instance))))
 
 
 ;; manipulation of datasets
diff --git a/test/clj_ml/data_test.clj b/test/clj_ml/data_test.clj
index efe3125..3b8cd01 100644
--- a/test/clj_ml/data_test.clj
+++ b/test/clj_ml/data_test.clj
@@ -100,14 +100,11 @@
     (is (sequential? seq))))
 
 
-(deftest working-sequences
+(deftest working-sequences-and-helpers
   (let [ds (make-dataset "test" [:a :b {:c [:d :e]}] [{:a 1 :b 2 :c :d} [4 5 :e]])]
     (is (= 2 (dataset-count ds)))
-    (let [dsm (map #(instance-to-map %1) (dataset-seq ds))]
-      (is (= 2 (count dsm)))
-      (is (= 1.0 (:a (first dsm))))
-      (let [dsb (make-dataset "test" [:a :b {:c [:d :e]}] dsm)]
-        (is (= 2 (dataset-count dsb)))))))
+    (is (= [{:a 1 :b 2 :c :d} {:a 4 :b 5 :c :e}] (dataset-as-maps ds)))
+    (is (= [{:a 1 :b 2 :c :d} {:a 4 :b 5 :c :e}] (map #(instance-to-map %1) (dataset-seq ds))))))
 
 (deftest dataset-instance-predicates
   (let [ds (make-dataset "test" [:a :b {:c [:d :e]}] [{:a 1 :b 2 :c :d} [4 5 :e]])
diff --git a/test/clj_ml/filters_test.clj b/test/clj_ml/filters_test.clj
index 90d3571..7914e73 100644
--- a/test/clj_ml/filters_test.clj
+++ b/test/clj_ml/filters_test.clj
@@ -187,7 +187,7 @@
         res (make-apply-filter :clj-batch
                                {:process add-max-diff-values
                                 :determine-dataset-format add-max-diff-attr} ds)]
-    (is (= (dataset-as-maps res)
-           [{:a 1 :max-diff 3}
+    (is (= [{:a 1 :max-diff 3}
             {:a 2 :max-diff 2}
-            {:a 4 :max-diff 0}]))))
+            {:a 4 :max-diff 0}]
+             (dataset-as-maps res)))))