Merge pull request #4459 from danbirken/panel-instance-name-fix

BUG: Fix Panel instance variable namespace issue GH3440

Author: cpcloud

doc/source/release.rst

@@ -121,6 +121,8 @@ pandas 0.13
     (:issue:`4405`, :issue:`4437`)
   - Fixed a py3 compat issue where bytes were being repr'd as tuples
     (:issue:`4455`)
+  - Fixed Panel attribute naming conflict if item is named 'a'
+    (:issue:`3440`)
 
 pandas 0.12
 ===========

pandas/core/panel.py

@@ -165,12 +165,12 @@ class Panel(NDFrame):
     """
 
     _AXIS_ORDERS = ['items', 'major_axis', 'minor_axis']
-    _AXIS_NUMBERS = dict([(a, i) for i, a in enumerate(_AXIS_ORDERS)])
+    _AXIS_NUMBERS = dict((a, i) for i, a in enumerate(_AXIS_ORDERS))
     _AXIS_ALIASES = {
         'major': 'major_axis',
         'minor': 'minor_axis'
     }
-    _AXIS_NAMES = dict([(i, a) for i, a in enumerate(_AXIS_ORDERS)])
+    _AXIS_NAMES = dict(enumerate(_AXIS_ORDERS))
     _AXIS_SLICEMAP = {
         'major_axis': 'index',
         'minor_axis': 'columns'

pandas/tests/test_panel.py

@@ -1340,6 +1340,12 @@ def test_rename(self):
     def test_get_attr(self):
         assert_frame_equal(self.panel['ItemA'], self.panel.ItemA)
 
+        # specific cases from #3440
+        self.panel['a'] = self.panel['ItemA']
+        assert_frame_equal(self.panel['a'], self.panel.a)
+        self.panel['i'] = self.panel['ItemA']
+        assert_frame_equal(self.panel['i'], self.panel.i)
+
     def test_group_agg(self):
         values = np.ones((10, 2)) * np.arange(10).reshape((10, 1))
         bounds = np.arange(5) * 2