BUG: inconsisten panel indexing with aligning frame (GH7763)

pandas/core/indexing.py

@@ -609,7 +609,13 @@ def _align_series(self, indexer, ser):
     def _align_frame(self, indexer, df):
         is_frame = self.obj.ndim == 2
         is_panel = self.obj.ndim >= 3
+
         if isinstance(indexer, tuple):
+
+            aligners = [not _is_null_slice(idx) for idx in indexer]
+            sum_aligners = sum(aligners)
+            single_aligner = sum_aligners == 1
+
             idx, cols = None, None
             sindexers = []
             for i, ix in enumerate(indexer):
@@ -626,13 +632,21 @@ def _align_frame(self, indexer, df):
 
             # panel
             if is_panel:
-                if len(sindexers) == 1 and idx is None and cols is None:
-                    if sindexers[0] == 0:
-                        df = df.T
-                    return self.obj.conform(df, axis=sindexers[0])
-                df = df.T
+
+                # need to conform to the convention
+                # as we are not selecting on the items axis
+                # and we have a single indexer
+                # GH 7763
+                if len(sindexers) == 1 and sindexers[0] != 0:
+                    df = df.T
+
+                if idx is None:
+                    idx = df.index
+                if cols is None:
+                    cols = df.columns
 
             if idx is not None and cols is not None:
+
                 if df.index.equals(idx) and df.columns.equals(cols):
                     val = df.copy().values
                 else:
@@ -655,21 +669,15 @@ def _align_frame(self, indexer, df):
                 val = df.reindex(index=ax).values
             return val
 
-        elif np.isscalar(indexer) and not is_frame:
+        elif np.isscalar(indexer) and is_panel:
             idx = self.obj.axes[1]
             cols = self.obj.axes[2]
 
             # by definition we are indexing on the 0th axis
-            if is_panel:
-                df = df.T
-
-            if idx.equals(df.index) and cols.equals(df.columns):
-                return df.copy().values
-
             # a passed in dataframe which is actually a transpose
             # of what is needed
-            elif idx.equals(df.columns) and cols.equals(df.index):
-                return df.T.copy().values
+            if idx.equals(df.index) and cols.equals(df.columns):
+                return df.copy().values
 
             return df.reindex(idx, columns=cols).values
 

pandas/tests/test_indexing.py

@@ -2291,6 +2291,33 @@ def test_panel_getitem(self):
         test1 = panel.ix[:, "2002"]
         tm.assert_panel_equal(test1,test2)
 
+    def test_panel_setitem(self):
+
+        # GH 7763
+        # loc and setitem have setting differences
+        np.random.seed(0)
+        index=range(3)
+        columns = list('abc')
+
+        panel = Panel({'A' : DataFrame(np.random.randn(3, 3), index=index, columns=columns),
+                       'B' : DataFrame(np.random.randn(3, 3), index=index, columns=columns),
+                       'C' : DataFrame(np.random.randn(3, 3), index=index, columns=columns)
+                       })
+
+        replace = DataFrame(np.eye(3,3), index=range(3), columns=columns)
+        expected = Panel({ 'A' : replace, 'B' : replace, 'C' : replace })
+
+        p = panel.copy()
+        for idx in list('ABC'):
+            p[idx] = replace
+        tm.assert_panel_equal(p, expected)
+
+        p = panel.copy()
+        for idx in list('ABC'):
+            p.loc[idx,:,:] = replace
+        tm.assert_panel_equal(p, expected)
+
+
     def test_panel_assignment(self):
 
         # GH3777

pandas/tests/test_panel.py

@@ -668,24 +668,42 @@ def test_ix_align(self):
 
     def test_ix_frame_align(self):
         from pandas import DataFrame
-        df = DataFrame(np.random.randn(2, 10))
-        df.sort_index(inplace=True)
-        p_orig = Panel(np.random.randn(3, 10, 2))
+        p_orig = tm.makePanel()
+        df = p_orig.ix[0].copy()
+        assert_frame_equal(p_orig['ItemA'],df)
 
         p = p_orig.copy()
         p.ix[0, :, :] = df
-        out = p.ix[0, :, :].T.reindex(df.index, columns=df.columns)
-        assert_frame_equal(out, df)
+        assert_panel_equal(p, p_orig)
 
         p = p_orig.copy()
         p.ix[0] = df
-        out = p.ix[0].T.reindex(df.index, columns=df.columns)
-        assert_frame_equal(out, df)
+        assert_panel_equal(p, p_orig)
+
+        p = p_orig.copy()
+        p.iloc[0, :, :] = df
+        assert_panel_equal(p, p_orig)
+
+        p = p_orig.copy()
+        p.iloc[0] = df
+        assert_panel_equal(p, p_orig)
+
+        p = p_orig.copy()
+        p.loc['ItemA'] = df
+        assert_panel_equal(p, p_orig)
+
+        p = p_orig.copy()
+        p.loc['ItemA', :, :] = df
+        assert_panel_equal(p, p_orig)
+
+        p = p_orig.copy()
+        p['ItemA'] = df
+        assert_panel_equal(p, p_orig)
 
         p = p_orig.copy()
         p.ix[0, [0, 1, 3, 5], -2:] = df
         out = p.ix[0, [0, 1, 3, 5], -2:]
-        assert_frame_equal(out, df.T.reindex([0, 1, 3, 5], p.minor_axis[-2:]))
+        assert_frame_equal(out, df.iloc[[0,1,3,5],[2,3]])
 
         # GH3830, panel assignent by values/frame
         for dtype in ['float64','int64']: