BUG: Series.hist raises with a one-row Series #110214

Author: s-celles

doc/source/whatsnew/v0.16.2.txt

@@ -116,6 +116,7 @@ Performance Improvements
 Bug Fixes
 ~~~~~~~~~
 
+- Bug in ``Series.hist`` raises an error when a one row ``Series`` was given (:issue:`10214`)
 - Bug where read_hdf store.select modifies the passed columns list when
   multi-indexed (:issue:`7212`)
 - Bug in ``Categorical`` repr with ``display.width`` of ``None`` in Python 3 (:issue:`10087`)

pandas/tests/test_graphics.py

@@ -3896,6 +3896,14 @@ def test_plotting_with_float_index_works(self):
         df.groupby('def')['val'].apply(lambda x: x.plot())
         tm.close()
 
+    def test_hist_single_row(self):
+        # GH10214
+        bins = np.arange(80, 100 + 2, 1)
+        df = DataFrame({"Name": ["AAA", "BBB"], "ByCol": [1, 2], "Mark": [85, 89]})
+        df["Mark"].hist(by=df["ByCol"], bins=bins)
+        df = DataFrame({"Name": ["AAA"], "ByCol": [1], "Mark": [85]})
+        df["Mark"].hist(by=df["ByCol"], bins=bins)
+
 
 def assert_is_valid_plot_return_object(objs):
     import matplotlib.pyplot as plt

pandas/tools/plotting.py

@@ -2846,8 +2846,9 @@ def hist_series(self, by=None, ax=None, grid=True, xlabelsize=None,
                             xlabelsize=xlabelsize, xrot=xrot, ylabelsize=ylabelsize, yrot=yrot,
                             **kwds)
 
-    if axes.ndim == 1 and len(axes) == 1:
-        return axes[0]
+    if hasattr(axes, 'ndim'):
+        if axes.ndim == 1 and len(axes) == 1:
+            return axes[0]
     return axes