Merge pull request matplotlib#3015 from tacaswell/date_stem_simplefix

Date stem simplefix

Author: efiring

CHANGELOG

@@ -10,6 +10,8 @@
 2014-04-27 Improved input clean up in Axes.{h|v}lines
            Coerce input into a 1D ndarrays (after dealing with units).
 
+2014-04-27 removed un-needed cast to float in stem
+
 2014-04-22 Added an example showing the difference between
            interpolation = 'none' and interpolation = 'nearest' in
            `imshow()` when saving vector graphics files.
@@ -20,6 +22,10 @@
 2014-04-08 Fixed a bug in parasite_axes.py by making a list out
            of a generator at line 263.
 
+2014-02-25 In backend_qt4agg changed from using update -> repaint under
+	   windows.  See comment in source near `self._priv_update` for
+	   longer explaination.
+
 2014-03-27 Added tests for pie ccw parameter. Removed pdf and svg images
            from tests for pie linewidth parameter.
 

lib/matplotlib/axes/_axes.py

@@ -2263,7 +2263,7 @@ def stem(self, *args, **kwargs):
         self.hold(True)
 
         # Assume there's at least one data array
-        y = np.asarray(args[0], dtype=np.float)
+        y = np.asarray(args[0])
         args = args[1:]
 
         # Try a second one

lib/matplotlib/tests/test_axes.py

@@ -1636,6 +1636,19 @@ def test_stem_args():
     ax.stem(x, y, 'r--', basefmt='b--')
 
 
+@cleanup
+def test_stem_dates():
+    fig, ax = plt.subplots(1, 1)
+    from dateutil import parser
+    x = parser.parse("2013-9-28 11:00:00")
+    y = 100
+
+    x1 = parser.parse("2013-9-28 12:00:00")
+    y1 = 200
+
+    ax.stem([x, x1], [y, y1], "*-")
+
+
 @image_comparison(baseline_images=['hist_stacked_stepfilled_alpha'])
 def test_hist_stacked_stepfilled_alpha():
     # make some data