Merge pull request #3533 from jreback/GH3492

BUG: Fixed bug in mixed frame assignment with aligned series (GH3492)

Author: jreback

RELEASE.rst

@@ -78,6 +78,7 @@ pandas 0.11.1
       (removed warning) (GH2786_), and fix (GH3230_)
     - Fix to_csv to handle non-unique columns (GH3495_)
   - Fixed bug in groupby with empty series referencing a variable before assignment. (GH3510_)
+  - Fixed bug in mixed-frame assignment with aligned series (GH3492_)
 
 .. _GH3164: https://github.com/pydata/pandas/issues/3164
 .. _GH2786: https://github.com/pydata/pandas/issues/2786
@@ -103,6 +104,7 @@ pandas 0.11.1
 .. _GH3448: https://github.com/pydata/pandas/issues/3448
 .. _GH3449: https://github.com/pydata/pandas/issues/3449
 .. _GH3495: https://github.com/pydata/pandas/issues/3495
+.. _GH3492: https://github.com/pydata/pandas/issues/3492
 .. _GH3493: https://github.com/pydata/pandas/issues/3493
 
 

doc/source/v0.11.1.txt

@@ -21,3 +21,4 @@ on GitHub for a complete list.
 
 .. _GH2437: https://github.com/pydata/pandas/issues/2437
 .. _GH3477: https://github.com/pydata/pandas/issues/3477
+.. _GH3492: https://github.com/pydata/pandas/issues/3492

pandas/core/indexing.py

@@ -124,8 +124,7 @@ def setter(item, v):
                 values = data.values
                 if np.prod(values.shape):
                     result, changed = com._maybe_upcast_indexer(values,plane_indexer,v,dtype=getattr(data,'dtype',None))
-                    if changed:
-                        self.obj[item] = result
+                    self.obj[item] = result
 
             labels = item_labels[het_idx]
 

pandas/tests/test_indexing.py

@@ -784,6 +784,21 @@ def test_dups_fancy_indexing(self):
 
         assert_frame_equal(df,result)
 
+    def test_indexing_mixed_frame_bug(self):
+
+        # GH3492
+        df=DataFrame({'a':{1:'aaa',2:'bbb',3:'ccc'},'b':{1:111,2:222,3:333}})
+
+        # this works, new column is created correctly
+        df['test']=df['a'].apply(lambda x: '_' if x=='aaa' else x)
+
+        # this does not work, ie column test is not changed
+        idx=df['test']=='_'
+        temp=df.ix[idx,'a'].apply(lambda x: '-----' if x=='aaa' else x)
+        df.ix[idx,'test']=temp
+        self.assert_(df.iloc[0,2] == '-----')
+
+        #if I look at df, then element [0,2] equals '_'. If instead I type df.ix[idx,'test'], I get '-----', finally by typing df.iloc[0,2] I get '_'.
 
 if __name__ == '__main__':
     import nose