BUG: Handle np strings in index.name in HDF pandas-dev#13492

Author: makmanalp

pandas/io/pytables.py

@@ -73,6 +73,14 @@ def _ensure_encoding(encoding):
     return encoding
 
 
+def _ensure_python_type(obj):
+    """ Ensure that non-python types get converted to python native type
+    equivalents."""
+    if isinstance(obj, np.generic):
+        return obj.item()
+    return obj
+
+
 Term = Expr
 
 
@@ -2567,7 +2575,7 @@ def read_index_node(self, node, start=None, stop=None):
         name = None
 
         if 'name' in node._v_attrs:
-            name = node._v_attrs.name
+            name = _ensure_decoded(_ensure_python_type(node._v_attrs.name))
 
         index_class = self._alias_to_class(getattr(node._v_attrs,
                                                    'index_class', ''))