Add info to docs

Author: udit710

doc/source/whatsnew/v3.0.0.rst

@@ -56,6 +56,7 @@ Other enhancements
 - :meth:`DataFrame.cummin`, :meth:`DataFrame.cummax`, :meth:`DataFrame.cumprod` and :meth:`DataFrame.cumsum` methods now have a ``numeric_only`` parameter (:issue:`53072`)
 - :meth:`DataFrame.ewm` now allows ``adjust=False`` when ``times`` is provided (:issue:`54328`)
 - :meth:`DataFrame.fillna` and :meth:`Series.fillna` can now accept ``value=None``; for non-object dtype the corresponding NA value will be used (:issue:`57723`)
+- :meth:`DataFrame.groupby` now accepts no fields for ``groupby`` by in :meth:`DataFrame.groupby` (:issue:`61160`)
 - :meth:`DataFrame.pivot_table` and :func:`pivot_table` now allow the passing of keyword arguments to ``aggfunc`` through ``**kwargs`` (:issue:`57884`)
 - :meth:`DataFrame.to_json` now encodes ``Decimal`` as strings instead of floats (:issue:`60698`)
 - :meth:`Series.cummin` and :meth:`Series.cummax` now supports :class:`CategoricalDtype` (:issue:`52335`)

pandas/core/frame.py

@@ -9155,7 +9155,6 @@ def groupby(
 
         if level is None and (by is None or by == []):
             by = Series(0, index=self.index)
-            # raise TypeError("You have to supply one of 'by' and 'level'")
 
         return DataFrameGroupBy(
             obj=self,

pandas/core/series.py

@@ -1975,7 +1975,6 @@ def groupby(
 
         if level is None and (by is None or by == []):
             by = Series(0, index=self.index)
-            # raise TypeError("You have to supply one of 'by' and 'level'")
         if not as_index:
             raise TypeError("as_index=False only valid with DataFrame")
 

pandas/tests/groupby/test_grouping.py

@@ -696,7 +696,7 @@ def test_groupby_level_with_nas(self, sort):
         tm.assert_series_equal(result, expected)
 
     def test_groupby_without_by(self):
-        # Test DataFrame.groupby() without any fields (global aggregation)
+        # GH 61160
         df = DataFrame({"A": [1, 2, 3, 4], "B": [10, 20, 30, 40]})
 
         # Test basic aggregation with no fields
@@ -715,41 +715,26 @@ def test_groupby_without_by(self):
         expected = Series([10])  # Sum of the values
         tm.assert_series_equal(result, expected)
 
-        # Test with conditional logic - should work with None/empty list too
+        # Test with conditional logic - should work with None/empty list
         groupby_fields = None
         result = df.groupby(groupby_fields).sum()
         expected = df.sum().to_frame().T
         tm.assert_frame_equal(result, expected)
 
-        # Test with empty list
         result = df.groupby([]).sum()
         tm.assert_frame_equal(result, expected)
 
     def test_groupby_args(self, multiindex_dataframe_random_data):
         # PR8618 and issue 8015
         frame = multiindex_dataframe_random_data
 
-        # No longer expecting errors when groupby() is called with no arguments
-        # This is now valid behavior that puts all rows in a single group
         result = frame.groupby().sum()
         expected = frame.sum().to_frame().T
         tm.assert_frame_equal(result, expected)
 
         result = frame.groupby(by=None, level=None).sum()
         tm.assert_frame_equal(result, expected)
 
-    # def test_groupby_args(self, multiindex_dataframe_random_data):
-    #     # PR8618 and issue 8015
-    #     frame = multiindex_dataframe_random_data
-
-    #     msg = "You have to supply one of 'by' and 'level'"
-    #     with pytest.raises(TypeError, match=msg):
-    #         frame.groupby()
-
-    #     msg = "You have to supply one of 'by' and 'level'"
-    #     with pytest.raises(TypeError, match=msg):
-    #         frame.groupby(by=None, level=None)
-
     @pytest.mark.parametrize(
         "sort,labels",
         [