From c863f89a7ae7fa8a80fc321b0c6e35ad23fc13fb Mon Sep 17 00:00:00 2001
From: MarcoGorelli <>
Date: Fri, 25 Nov 2022 12:35:12 +0000
Subject: [PATCH 1/3] dont set name if dataframe

---
 doc/source/whatsnew/v1.5.3.rst     | 1 +
 pandas/core/groupby/generic.py     | 3 ++-
 pandas/tests/groupby/test_apply.py | 1 +
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/doc/source/whatsnew/v1.5.3.rst b/doc/source/whatsnew/v1.5.3.rst
index e7428956c50b5..e0bcd81805cc1 100644
--- a/doc/source/whatsnew/v1.5.3.rst
+++ b/doc/source/whatsnew/v1.5.3.rst
@@ -16,6 +16,7 @@ Fixed regressions
 - Fixed performance regression in :meth:`Series.isin` when ``values`` is empty (:issue:`49839`)
 - Fixed regression in :meth:`DataFrameGroupBy.transform` when used with ``as_index=False`` (:issue:`49834`)
 - Enforced reversion of ``color`` as an alias for ``c`` and ``size`` as an alias for ``s`` in function :meth:`DataFrame.plot.scatter` (:issue:`49732`)
+- Fixed regression in :meth:`SeriesGroupBy.apply` setting a ``name`` attribute on the result if the result was a :class:`DataFrame` (:issue:`49907`)
 -
 
 .. ---------------------------------------------------------------------------
diff --git a/pandas/core/groupby/generic.py b/pandas/core/groupby/generic.py
index a9ef1fca7e8e7..7dce4755e861e 100644
--- a/pandas/core/groupby/generic.py
+++ b/pandas/core/groupby/generic.py
@@ -401,7 +401,8 @@ def _wrap_applied_output(
                 not_indexed_same=not_indexed_same,
                 is_transform=is_transform,
             )
-            result.name = self.obj.name
+            if isinstance(result, Series):
+                result.name = self.obj.name
             return result
         else:
             # GH #6265 #24880
diff --git a/pandas/tests/groupby/test_apply.py b/pandas/tests/groupby/test_apply.py
index af523928e0bc8..a130865bb5534 100644
--- a/pandas/tests/groupby/test_apply.py
+++ b/pandas/tests/groupby/test_apply.py
@@ -334,6 +334,7 @@ def f(piece):
     result = grouped.apply(f)
 
     assert isinstance(result, DataFrame)
+    assert not hasattr(result, "name")
     tm.assert_index_equal(result.index, ts.index)
 
 

From 191b4cb5179639b5b612632cabe1202293597b33 Mon Sep 17 00:00:00 2001
From: MarcoGorelli <>
Date: Fri, 25 Nov 2022 16:16:57 +0000
Subject: [PATCH 2/3] use ndim in check, add gh reference to test

---
 pandas/core/groupby/generic.py     | 2 +-
 pandas/tests/groupby/test_apply.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/groupby/generic.py b/pandas/core/groupby/generic.py
index 7dce4755e861e..820155eadd1ac 100644
--- a/pandas/core/groupby/generic.py
+++ b/pandas/core/groupby/generic.py
@@ -401,7 +401,7 @@ def _wrap_applied_output(
                 not_indexed_same=not_indexed_same,
                 is_transform=is_transform,
             )
-            if isinstance(result, Series):
+            if result.ndim == 1:
                 result.name = self.obj.name
             return result
         else:
diff --git a/pandas/tests/groupby/test_apply.py b/pandas/tests/groupby/test_apply.py
index a130865bb5534..0d5ab9a4f1acc 100644
--- a/pandas/tests/groupby/test_apply.py
+++ b/pandas/tests/groupby/test_apply.py
@@ -334,7 +334,7 @@ def f(piece):
     result = grouped.apply(f)
 
     assert isinstance(result, DataFrame)
-    assert not hasattr(result, "name")
+    assert not hasattr(result, "name")  # GH49907
     tm.assert_index_equal(result.index, ts.index)
 
 

From 962d02abcb1716b4621681bcee4090e48c54a5a0 Mon Sep 17 00:00:00 2001
From: MarcoGorelli <>
Date: Fri, 25 Nov 2022 16:45:51 +0000
Subject: [PATCH 3/3] back to isinstance

---
 pandas/core/groupby/generic.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/groupby/generic.py b/pandas/core/groupby/generic.py
index 820155eadd1ac..7dce4755e861e 100644
--- a/pandas/core/groupby/generic.py
+++ b/pandas/core/groupby/generic.py
@@ -401,7 +401,7 @@ def _wrap_applied_output(
                 not_indexed_same=not_indexed_same,
                 is_transform=is_transform,
             )
-            if result.ndim == 1:
+            if isinstance(result, Series):
                 result.name = self.obj.name
             return result
         else: