FIX: if the first elements of an array are masked keep checking

anntzer · tacaswell · commit 158ee506676a · 2019-06-02T23:30:50.000-04:00
closes #14356
diff --git a/lib/matplotlib/tests/test_units.py b/lib/matplotlib/tests/test_units.py
@@ -153,3 +153,14 @@ def test_jpl_barh_units():
 def test_empty_arrays():
     # Check that plotting an empty array with a dtype works
     plt.scatter(np.array([], dtype='datetime64[ns]'), np.array([]))
+
+
+def test_scatter_element0_masked():
+
+    times = np.arange('2005-02', '2005-03', dtype='datetime64[D]')
+
+    y = np.arange(len(times))
+    y[0] = np.nan
+    fig, ax = plt.subplots()
+    ax.scatter(times, y)
+    fig.canvas.draw()
diff --git a/lib/matplotlib/units.py b/lib/matplotlib/units.py
@@ -64,6 +64,8 @@ def _is_natively_supported(x):
     if np.iterable(x):
         # Assume lists are homogeneous as other functions in unit system.
         for thisx in x:
+            if thisx is ma.masked:
+                continue
             return isinstance(thisx, Number) and not isinstance(thisx, Decimal)
     else:
         return isinstance(x, Number) and not isinstance(x, Decimal)
@@ -144,6 +146,8 @@ def is_numlike(x):
         """
         if np.iterable(x):
             for thisx in x:
+                if thisx is ma.masked:
+                    continue
                 return isinstance(thisx, Number)
         else:
             return isinstance(x, Number)
