added whatsnew

bobhaffner · bobhaffner · commit 5fa71e1dd8a4 · 2017-11-25T13:03:40.000-06:00
diff --git a/doc/source/whatsnew/v0.21.1.txt b/doc/source/whatsnew/v0.21.1.txt
@@ -103,7 +103,7 @@ Groupby/Resample/Rolling
 - Bug in ``DataFrame.resample(...).apply(...)`` when there is a callable that returns different columns (:issue:`15169`)
 - Bug in ``DataFrame.resample(...)`` when there is a time change (DST) and resampling frequecy is 12h or higher (:issue:`15549`)
 - Bug in ``pd.DataFrameGroupBy.count()`` when counting over a datetimelike column (:issue:`13393`)
--
+- Bug when grouping by a single column and aggregating with a class like`list` or `tuple` (:issue:`18079`)
 -
 -
 

Original file line number	Diff line number	Diff line change
`@@ -103,7 +103,7 @@ Groupby/Resample/Rolling`
`103`	`103`	- Bug in ``DataFrame.resample(...).apply(...)`` when there is a callable that returns different columns (:issue:`15169`)
`104`	`104`	- Bug in ``DataFrame.resample(...)`` when there is a time change (DST) and resampling frequecy is 12h or higher (:issue:`15549`)
`105`	`105`	- Bug in ``pd.DataFrameGroupBy.count()`` when counting over a datetimelike column (:issue:`13393`)
`106`		`--`
	`106`	+- Bug when grouping by a single column and aggregating with a class like`list` or `tuple` (:issue:`18079`)
`107`	`107`	`-`
`108`	`108`	`-`
`109`	`109`