[FIX] stats: Handle empty array

Orange/statistics/util.py

@@ -370,6 +370,8 @@ def stats(X, weights=None, compute_variance=False):
             X.shape[0] - non_zero,
             non_zero))
     else:
+        if X.ndim == 1:
+            X = X[:, None]
         nans = (pandas.isnull(X).sum(axis=0) + (X == "").sum(axis=0)) \
             if X.size else np.zeros(X.shape[1])
         return np.column_stack((

Orange/tests/test_basic_stats.py

@@ -28,6 +28,10 @@ def test_domain_basic_stats(self):
         self.assertStatsEqual(domain_stats.stats,
                               attr_stats + class_var_stats + meta_stats)
 
+    def test_empty_table(self):
+        domain_stats = DomainBasicStats(self.zoo[:0])
+        self.assertEqual(len(domain_stats.stats), 17)
+
     def test_speed(self):
         n, m = 10, 10000
         data = Table.from_numpy(None, np.random.rand(n, m))

Orange/tests/test_statistics.py

@@ -170,6 +170,18 @@ def test_stats_non_numeric(self):
                                            [np.inf, -np.inf, 0, 0, 2, 1],
                                            [np.inf, -np.inf, 0, 0, 0, 3]])
 
+    def test_stats_empty(self):
+        X = np.array([])
+        np.testing.assert_equal(stats(X), [[np.inf, -np.inf, 0, 0, 0, 0]])
+
+        X = np.zeros((0,))
+        np.testing.assert_equal(stats(X), [[np.inf, -np.inf, 0, 0, 0, 0]])
+
+        X = np.zeros((0, 4))
+        np.testing.assert_equal(stats(X), [[np.inf, -np.inf, 0, 0, 0, 0]] * 4)
+
+
+
     def test_stats_long_string_mem_use(self):
         X = np.full((1000, 1000), "a", dtype=object)
         t = time.time()

Orange/widgets/data/tests/test_owtable.py

@@ -46,6 +46,12 @@ def test_input_data(self):
         self.send_signal(self.widget.Inputs.data, None, 1)
         self.assertEqual(self.widget.tabs.count(), 1)
 
+    def test_input_data_empty(self):
+        self.send_signal(self.widget.Inputs.data, self.data[:0])
+        output = self.get_output(self.widget.Outputs.annotated_data)
+        self.assertIsInstance(output, Table)
+        self.assertEqual(len(output), 0)
+
     def test_data_model(self):
         self.send_signal(self.widget.Inputs.data, self.data, 1)
         self.assertEqual(self.widget.tabs.widget(0).model().rowCount(),