COMPAT: Category pickle compat

Author: jreback

pandas/core/categorical.py

@@ -187,6 +187,8 @@ class Categorical(PandasObject):
 
     # For comparisons, so that numpy uses our implementation if the compare ops, which raise
     __array_priority__ = 1000
+    ordered = False
+    name = None
 
     def __init__(self, values, categories=None, ordered=None, name=None, fastpath=False,
                  levels=None):
@@ -718,6 +720,19 @@ def __array__(self, dtype=None):
             return np.asarray(ret, dtype)
         return ret
 
+    def __setstate__(self, state):
+        """Necessary for making this object picklable"""
+        if not isinstance(state, dict):
+            raise Exception('invalid pickle state')
+
+        if 'labels' in state:
+            state['_codes'] = state.pop('labels')
+        if '_levels' in state:
+            state['categories'] = state.pop('_levels')
+
+        for k, v in compat.iteritems(state):
+            setattr(self,k,v)
+
     @property
     def T(self):
         return self