Merge jreback's suggested changes. Also handle rewrite and MultiIndex.

And, make sure that non_index_axes is preserved if it was written by
legacy code.

pandas/io/pytables.py

@@ -11,8 +11,7 @@
 import itertools
 import warnings
 import os
-from six import string_types
-from tables.exceptions import NoSuchNodeError
+
 import numpy as np
 import pandas as pd
 from pandas import (Series, DataFrame, Panel, Panel4D, Index,
@@ -42,6 +41,8 @@
 import pandas.algos as algos
 import pandas.tslib as tslib
 
+from tables.exceptions import NoSuchNodeError, NodeError
+
 from contextlib import contextmanager
 from distutils.version import LooseVersion
 
@@ -1513,6 +1514,10 @@ def cvalues(self):
         """ return my cython values """
         return self.values
 
+    @property
+    def handle(self):
+        return self._handle
+
     def __iter__(self):
         return iter(self.values)
 
@@ -2048,8 +2053,12 @@ def get_attr(self):
         self.values = getattr(self.attrs, self.kind_attr, None)
         if self.values is None:
             try:
-                self.values = self._handle.get_node(self.attrs._v_node._v_parent,
-                                                    self.kind_attr)[:].tolist()
+                data = self.handle.get_node(self.attrs._v_node._v_parent, self.kind_attr)[:]
+                if len(data.shape) > 1 and data.shape[1] > 1: # multiIndex
+                    self.values = map(tuple, data.tolist())
+                else:
+                    self.values = data.tolist()
+
             except NoSuchNodeError:
                 pass
         self.dtype = getattr(self.attrs, self.dtype_attr, None)
@@ -2059,9 +2068,18 @@ def get_attr(self):
     def set_attr(self):
         """ set the data for this colummn """
         #setattr(self.attrs, self.kind_attr, self.values)
-        self._handle.create_carray(self.attrs._v_node._v_parent,
+        try:
+            self.handle.create_carray(self.attrs._v_node._v_parent,
                                    self.kind_attr,
                                    obj=np.array(self.values))
+        except NodeError as e: 
+            self.handle.remove_node(self.attrs._v_node._v_parent,
+                                   self.kind_attr)
+            self.handle.create_carray(self.attrs._v_node._v_parent,
+                                   self.kind_attr,
+                                   obj=np.array(self.values))    
+        except Exception as e: # for debugging
+            raise      
         setattr(self.attrs, self.meta_attr, self.meta)
         if self.dtype is not None:
             setattr(self.attrs, self.dtype_attr, self.dtype)
@@ -3033,20 +3051,39 @@ def set_info(self):
         self.attrs.info = self.info
 
     def set_non_index_axes(self):
-        replacement = []
-        for dim, flds in  self.non_index_axes:
-            name = "non_index_axes_%d" %  dim
-            self._handle.create_carray(self.attrs._v_node, name, obj=np.array(flds))
-            replacement.append((dim, name))
+        """ Write the axes to carrays """
+        def f(dim, flds):
+            name = "non_index_axes_%d" % dim
+            try:
+                self._handle.create_carray(self.attrs._v_node, name, obj=np.array(flds))
+            except ValueError as e: 
+                # Should probably make this check:
+                #if e.message == "unknown type: 'object'":
+                #    raise ValueError("axis {} has dtype 'object' which cannot be saved to carray".format(dim))
+                raise                
+            except NodeError as e: 
+                self._handle.remove_node(self.attrs._v_node, name)
+                self._handle.create_carray(self.attrs._v_node, name, obj=np.array(flds))                
+            return dim, flds
+
+        replacement = [f(dim, flds) for dim, flds in self.non_index_axes]
         self.attrs.non_index_axes = replacement
 
     def get_non_index_axes(self):
-        non_index_axes = getattr(self.attrs, 'non_index_axes', [])
-        new = []
-        for dim, flds in non_index_axes:
+        """Load the non-index axes from their carrays.  This is a pass-through
+        for tables stored prior to v0.17"""
+        def f(dim, flds):
             if isinstance(flds, string_types):
-                flds = self._handle.get_node(self.attrs._v_node, flds)[:].tolist()
-            new.append((dim, flds))
+                flds = self._handle.get_node(self.attrs._v_node, flds)[:]
+                if len(flds.shape) > 1 and flds.shape[1] > 1:
+                    flds = map(tuple, flds.tolist())
+                else:
+                    flds = flds.tolist()
+                return dim, flds
+            else:
+                return dim, flds #if not a string presumably pre v17 list
+        non_index_axes = getattr(self.attrs, 'non_index_axes', [])
+        new = [f(dim, flds) for dim, flds in non_index_axes] 
         return new
 
     def set_attrs(self):