Merge pull request #9853 from sinhrks/hist_char

BUG: plot(kind=hist) results in TypeError if it contains non-numeric data

Author: jreback

doc/source/whatsnew/v0.16.1.txt

@@ -107,6 +107,7 @@ Bug Fixes
 
 - Bug in plotting continuously using ``secondary_y`` may not show legend properly. (:issue:`9610`, :issue:`9779`)
 
+- Bug in ``DataFrame.plot(kind="hist")`` results in ``TypeError`` when ``DataFrame`` contains non-numeric columns  (:issue:`9853`)
 
 - Bug in ``Series.quantile`` on empty Series of type ``Datetime`` or ``Timedelta`` (:issue:`9675`)
 - Bug in ``where`` causing incorrect results when upcasting was required (:issue:`9731`)

pandas/tests/test_graphics.py

@@ -678,6 +678,18 @@ def test_hist_df_kwargs(self):
         ax = df.plot(kind='hist', bins=5)
         self.assertEqual(len(ax.patches), 10)
 
+    @slow
+    def test_hist_df_with_nonnumerics(self):
+        # GH 9853
+        with tm.RNGContext(1):
+            df = DataFrame(np.random.randn(10, 4), columns=['A', 'B', 'C', 'D'])
+        df['E'] = ['x', 'y'] * 5
+        ax = df.plot(kind='hist', bins=5)
+        self.assertEqual(len(ax.patches), 20)
+
+        ax = df.plot(kind='hist') # bins=10
+        self.assertEqual(len(ax.patches), 40)
+
     @slow
     def test_hist_legacy(self):
         _check_plot_works(self.ts.hist)

pandas/tools/plotting.py

@@ -1948,7 +1948,8 @@ def __init__(self, data, bins=10, bottom=0, **kwargs):
     def _args_adjust(self):
         if com.is_integer(self.bins):
             # create common bin edge
-            values = np.ravel(self.data.values)
+            values = self.data.convert_objects()._get_numeric_data()
+            values = np.ravel(values)
             values = values[~com.isnull(values)]
 
             hist, self.bins = np.histogram(values, bins=self.bins,