[FIX] Normalizer: Retain attributes of attributes

Orange/preprocess/normalize.py

@@ -1,6 +1,6 @@
 import numpy as np
 
-from Orange.data import ContinuousVariable, Domain
+from Orange.data import Domain
 from Orange.statistics import distribution
 from Orange.util import Reprable
 from .preprocess import Normalize
@@ -51,25 +51,15 @@ def normalize_by_sd(self, dist, var):
             compute_val = Norm(var, avg, 1 / sd)
         else:
             compute_val = Norm(var, 0, 1 / sd)
-
-        return ContinuousVariable(
-            var.name,
-            compute_value=compute_val,
-            sparse=var.sparse,
-        )
+        return var.copy(compute_value=compute_val)
 
     def normalize_by_span(self, dist, var):
         dma, dmi = (dist.max(), dist.min()) if dist.shape[1] else (np.nan, np.nan)
         diff = dma - dmi
         if diff < 1e-15:
             diff = 1
         if self.zero_based:
-            return ContinuousVariable(
-                var.name,
-                compute_value=Norm(var, dmi, 1 / diff),
-                sparse=var.sparse)
+            compute_val = Norm(var, dmi, 1 / diff)
         else:
-            return ContinuousVariable(
-                var.name,
-                compute_value=Norm(var, (dma + dmi) / 2, 2 / diff),
-                sparse=var.sparse)
+            compute_val = Norm(var, (dma + dmi) / 2, 2 / diff)
+        return var.copy(compute_value=compute_val)

Orange/tests/test_normalize.py

@@ -142,3 +142,18 @@ def test_datetime_normalization(self):
                     [0., '2003-07-23', 'a', 'b', -1., '?', 0., 'b', '?', 'b', 0],
                     [0., '1967-03-12', 'a', 'b', 1., 'b', -1.225, 'c', '?', 'c', 1]]
         self.compare_tables(data_norm, solution)
+
+    def test_retain_vars_attributes(self):
+        data = Table("iris")
+        attributes = {"foo": "foo", "baz": 1}
+        data.domain.attributes[0].attributes = attributes
+        self.assertDictEqual(
+            Normalize(norm_type=Normalize.NormalizeBySD)(
+                data).domain.attributes[0].attributes, attributes)
+        self.assertDictEqual(
+            Normalize(norm_type=Normalize.NormalizeBySpan)(
+                data).domain.attributes[0].attributes, attributes)
+
+
+if __name__ == "__main__":
+    unittest.main()