FIX: Fix shape of hist output when input is multidimensional empty list

hershen · hershen · commit 7b81ca55ee21 · 2019-02-05T11:13:58.000-08:00
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -6573,7 +6573,7 @@ def hist(self, x, bins=None, range=None, density=None, weights=None,
         # basic input validation
         input_empty = np.size(x) == 0
         # Massage 'x' for processing.
-        if input_empty:
+        if input_empty and len(x) == 0:
             x = [np.array([])]
         else:
             x = cbook._reshape_2D(x, 'x')
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -1665,6 +1665,20 @@ def test_hist_datetime_datasets():
     ax.hist(data, stacked=False)
 
 
+@pytest.mark.parametrize('data, expected_number_of_hists',
+                         [([], 1),
+                          ([[]], 1),
+                          ([[], []], 2)])
+def test_hist_with_empty_input(data, expected_number_of_hists):
+    hists, _, _ = plt.hist(data)
+    hists = np.asarray(hists)
+
+    if hists.ndim == 1:
+        assert 1 == expected_number_of_hists
+    else:
+        assert hists.shape[0] == expected_number_of_hists
+
+
 def contour_dat():
     x = np.linspace(-3, 5, 150)
     y = np.linspace(-3, 5, 120)
