BUG: barplot with log=True not working for values smaller than 1

Author: sinhrks

doc/source/whatsnew/v0.16.1.txt

@@ -144,8 +144,8 @@ Bug Fixes
 - Bug in ``MultiIndex.sortlevel()`` results in unicode level name breaks (:issue:`9875`)
 - Bug in which ``groupby.transform`` incorrectly enforced output dtypes to match input dtypes. (:issue:`9807`)
 
-
-
+- Bug in bar plot with ``log=True`` raises ``TypeError`` if all values are less than 1 (:issue:`9905`)
+- Bug in horizontal bar plot ignores ``log=True`` (:issue:`9905`)
 
 
 

pandas/tests/test_graphics.py

@@ -592,6 +592,26 @@ def test_bar_log(self):
 
         ax = Series([200, 500]).plot(log=True, kind='bar')
         assert_array_equal(ax.yaxis.get_ticklocs(), expected)
+        tm.close()
+
+        ax = Series([200, 500]).plot(log=True, kind='barh')
+        assert_array_equal(ax.xaxis.get_ticklocs(), expected)
+        tm.close()
+
+        # GH 9905
+        expected = np.array([1.0e-03, 1.0e-02, 1.0e-01, 1.0e+00])
+
+        if not self.mpl_le_1_2_1:
+            expected = np.hstack((1.0e-04, expected, 1.0e+01))
+
+        ax = Series([0.1, 0.01, 0.001]).plot(log=True, kind='bar')
+        assert_array_equal(ax.get_ylim(), (0.001, 0.10000000000000001))
+        assert_array_equal(ax.yaxis.get_ticklocs(), expected)
+        tm.close()
+
+        ax = Series([0.1, 0.01, 0.001]).plot(log=True, kind='barh')
+        assert_array_equal(ax.get_xlim(), (0.001, 0.10000000000000001))
+        assert_array_equal(ax.xaxis.get_ticklocs(), expected)
 
     @slow
     def test_bar_ignore_index(self):

pandas/tools/plotting.py

@@ -1824,21 +1824,19 @@ def _get_plot_function(self):
         if self.kind == 'bar':
             def f(ax, x, y, w, start=None, **kwds):
                 start = start + self.bottom
-                return ax.bar(x, y, w, bottom=start,log=self.log, **kwds)
+                return ax.bar(x, y, w, bottom=start, log=self.log, **kwds)
         elif self.kind == 'barh':
+
             def f(ax, x, y, w, start=None, log=self.log, **kwds):
                 start = start + self.left
-                return ax.barh(x, y, w, left=start, **kwds)
+                return ax.barh(x, y, w, left=start, log=self.log, **kwds)
         else:
             raise ValueError("BarPlot kind must be either 'bar' or 'barh'")
 
         return f
 
     def _make_plot(self):
         import matplotlib as mpl
-        # mpl decided to make their version string unicode across all Python
-        # versions for mpl >= 1.3 so we have to call str here for python 2
-        mpl_le_1_2_1 = str(mpl.__version__) <= LooseVersion('1.2.1')
 
         colors = self._get_colors()
         ncolors = len(colors)
@@ -1862,11 +1860,8 @@ def _make_plot(self):
                 kwds['ecolor'] = mpl.rcParams['xtick.color']
 
             start = 0
-            if self.log:
+            if self.log and (y >= 1).all():
                 start = 1
-                if any(y < 1):
-                    # GH3254
-                    start = 0 if mpl_le_1_2_1 else None
 
             if self.subplots:
                 w = self.bar_width / 2