BUG: work around mpl 1.2.1 regression, bar(log=True,bottom=None)) GH3254

Author: y-p

pandas/tests/test_graphics.py

@@ -408,7 +408,14 @@ def test_bar_center(self):
     def test_bar_log(self):
         df = DataFrame({'A': [3] * 5, 'B': range(5)}, index=range(5))
         ax = df.plot(kind='bar', grid=True,log=True)
-        self.assertEqual(ax.yaxis.get_ticklocs()[0],0.1)
+        self.assertEqual(ax.yaxis.get_ticklocs()[0],1.0)
+
+        p1 = Series([200,500]).plot(log=True,kind='bar')
+        p2 = DataFrame([Series([200,300]),Series([300,500])]).plot(log=True,kind='bar',subplots=True)
+
+        (p1.yaxis.get_ticklocs() == np.array([ 0.625,  1.625]))
+        (p2[0].yaxis.get_ticklocs() == np.array([ 100., 1000.])).all()
+        (p2[1].yaxis.get_ticklocs() == np.array([ 100., 1000.])).all()
 
     @slow
     def test_boxplot(self):

pandas/tools/plotting.py

@@ -1354,6 +1354,7 @@ def _get_colors(self):
         return colors
 
     def _make_plot(self):
+        import matplotlib as mpl
         colors = self._get_colors()
         rects = []
         labels = []
@@ -1371,10 +1372,15 @@ def _make_plot(self):
             kwds = self.kwds.copy()
             kwds['color'] = colors[i % len(colors)]
 
+            # default, GH3254
+            # I tried, I really did.
+            start = 0 if mpl.__version__ == "1.2.1" else None
             if self.subplots:
                 ax = self._get_ax(i)  # self.axes[i]
-                rect = bar_f(ax, self.ax_pos, y,
-                             self.bar_width, **kwds)
+
+                rect = bar_f(ax, self.ax_pos, y,  self.bar_width,
+                             start = start,
+                             **kwds)
                 ax.set_title(label)
             elif self.stacked:
                 mask = y > 0
@@ -1385,6 +1391,7 @@ def _make_plot(self):
                 neg_prior = neg_prior + np.where(mask, 0, y)
             else:
                 rect = bar_f(ax, self.ax_pos + i * 0.75 / K, y, 0.75 / K,
+                             start = start,
                               label=label, **kwds)
             rects.append(rect)
             labels.append(label)