Merge pull request #5083 from ales-erjavec/fixes/model-impute-no-backmap

[FIX] impute: Remove class vars from input data for ReplaceUnknownsModel

Author: janezd

Orange/preprocess/impute.py

@@ -160,19 +160,20 @@ def __init__(self, variable, model):
 
     def __call__(self, data):
         if isinstance(data, Orange.data.Instance):
-            column = np.array([float(data[self.variable])])
-        else:
-            column = np.array(data.get_column_view(self.variable)[0],
-                              copy=True)
+            data = Orange.data.Table.from_list(data.domain, [data])
+        domain = data.domain
+        column = np.array(data.get_column_view(self.variable)[0], copy=True)
 
         mask = np.isnan(column)
         if not np.any(mask):
             return column
 
-        if isinstance(data, Orange.data.Instance):
-            predicted = self.model(data)
-        else:
-            predicted = self.model(data[mask])
+        if domain.class_vars:
+            # cannot have class var in domain (due to backmappers in model)
+            data = data.transform(
+                Orange.data.Domain(domain.attributes, None, domain.metas)
+            )
+        predicted = self.model(data[mask])
         column[mask] = predicted
         return column
 

Orange/tests/test_impute.py

@@ -229,9 +229,12 @@ def test_replacement(self):
         domain = data.Domain(
             (data.DiscreteVariable("A", values=("0", "1", "2")),
              data.ContinuousVariable("B"),
-             data.ContinuousVariable("C"))
+             data.ContinuousVariable("C")),
+            # the class is here to ensure the backmapper in model does not
+            # run and raise exception
+            data.DiscreteVariable("Z", values=("P", "M"))
         )
-        table = data.Table.from_numpy(domain, np.array(X))
+        table = data.Table.from_numpy(domain, np.array(X), [0,] * 3)
 
         v = impute.Model(MajorityLearner())(table, domain[0])
         self.assertTrue(np.all(np.isfinite(v.compute_value(table))))