ERR/API: Raise NotImplementedError when Panel operator function is not implemented, #7692

Author: terrytangyuan

doc/source/whatsnew/v0.17.0.txt

@@ -1108,7 +1108,7 @@ Bug Fixes
 - Bug causes memory leak in time-series line and area plot (:issue:`9003`)
 
 - Bug when setting a ``Panel`` sliced along the major or minor axes when the right-hand side is a ``DataFrame`` (:issue:`11014`)
-
+- Bug that returns ``None`` and does not raise ``NotImplementedError`` when operator functions (e.g. ``.add``) of ``Panel`` are not implemented (:issue:`7692`)
 
 - Bug in line and kde plot cannot accept multiple colors when ``subplots=True`` (:issue:`9894`)
 - Bug in ``DataFrame.plot`` raises ``ValueError`` when color name is specified by multiple characters (:issue:`10387`)

pandas/core/panel.py

@@ -679,6 +679,10 @@ def _combine(self, other, func, axis=0):
             return self._combine_frame(other, func, axis=axis)
         elif np.isscalar(other):
             return self._combine_const(other, func)
+        else:
+            raise NotImplementedError(str(type(other)) + 
+                ' is not supported in combine operation with ' + 
+                str(type(self)))
 
     def _combine_const(self, other, func):
         new_values = func(self.values, other)

pandas/tests/test_panel.py

@@ -7,6 +7,7 @@
 import nose
 
 import numpy as np
+import pandas as pd
 
 from pandas import Series, DataFrame, Index, isnull, notnull, pivot, MultiIndex
 from pandas.core.datetools import bday
@@ -354,6 +355,16 @@ def test_combinePanel(self):
     def test_neg(self):
         self.assert_panel_equal(-self.panel, self.panel * -1)
 
+    # issue 7692
+    def test_raise_when_not_implemented(self):
+        p = Panel(np.arange(3*4*5).reshape(3,4,5), items=['ItemA','ItemB','ItemC'], 
+            major_axis=pd.date_range('20130101',periods=4),minor_axis=list('ABCDE'))
+        d = p.sum(axis=1).ix[0]
+        ops = ['add', 'sub', 'mul', 'truediv', 'floordiv', 'div', 'mod', 'pow']
+        for op in ops:
+            with self.assertRaises(NotImplementedError):
+                getattr(p,op)(d, axis=0)
+
     def test_select(self):
         p = self.panel