BUG: fix borked data-copying iteritems performance affecting DataFrame and SparseDataFrame. close #2273

Author: wesm

RELEASE.rst

@@ -37,6 +37,7 @@ pandas 0.9.2
 
 **Bug fixes**
 
+  - Fix performance regression in SparseDataFrame arithmetic and pickling
   - Fixes bug when negative period passed to Series/DataFrame.diff (#2266)
 
 pandas 0.9.1

pandas/core/frame.py

@@ -637,7 +637,7 @@ def keys(self):
     def iteritems(self):
         """Iterator over (column, series) pairs"""
         for i, k in enumerate(self.columns):
-            yield (k,self.take([i],axis=1)[k])
+            yield k, self.icol(i)
 
     def iterrows(self):
         """