fixup! BUG: Fix/test SparseSeries/SparseDataFrame stack/unstack

kernc · kernc · commit 2da39c2647fb · 2017-07-11T18:14:26.000+02:00
diff --git a/pandas/core/reshape/reshape.py b/pandas/core/reshape/reshape.py
@@ -534,7 +534,7 @@ def factorize(index):
         new_values = new_values[mask]
         new_index = new_index[mask]
 
-    klass = SparseSeries if isinstance(frame, SparseDataFrame) else Series
+    klass = type(frame)._constructor_sliced
     return klass(new_values, index=new_index)
 
 
