Avoid second coding, now that we respect order for unordered

Author: TomAugspurger

pandas/core/categorical.py

@@ -312,14 +312,7 @@ def __init__(self, values, categories=None, ordered=False, fastpath=False):
                 raise NotImplementedError("> 1 ndim Categorical are not "
                                           "supported at this time")
 
-            # categories = self.dtype._validate_categories(categories)
             dtype = CategoricalDtype(categories, ordered)
-            # XXX: would like to avoid this second coding
-            # could do something like unique() instead of factorize?
-            # will still be slower though.
-            # Issue is if there already exists a CategoricalDtype with
-            # `categories`, then the codes might not match up.
-            codes = _get_codes_for_values(values, dtype.categories)
 
         else:
             # there were two ways if categories are present