whatsnew

doc/source/whatsnew/v1.5.0.rst

@@ -82,17 +82,32 @@ did not have the same index as the input.
 
 .. code-block:: ipython
 
+ In [3]: df.groupby('a', dropna=True).transform(lambda x: x.sum())
+ Out[3]:
+ b
+ 0 5
+ 1 5
+
  In [3]: df.groupby('a', dropna=True).transform(lambda x: x)
  Out[3]:
  b
  0 2
  1 3
 
+ In [3]: df.groupby('a', dropna=True).transform('sum')
+ Out[3]:
+ b
+ 0 5
+ 1 5
+ 2 5
+
 *New behavior*:
 
 .. ipython:: python
 
+ df.groupby('a', dropna=True).transform(lambda x: x.sum())
  df.groupby('a', dropna=True).transform(lambda x: x)
+ df.groupby('a', dropna=True).transform('sum')
 
 .. _whatsnew_150.notable_bug_fixes.notable_bug_fix2: