DEPR: set_axis inplace keyword (pandas-dev#48130)

* ENH: copy keyword to set_axis

* GH ref

* fix test

* fix test

* troubleshoot mypy

* mypy fixup

* test inplace=True/copy=False case

* DEPR: inplace keyword in set_axis

* GH ref

doc/source/whatsnew/v1.5.0.rst

@@ -841,6 +841,7 @@ Other Deprecations
 - Deprecated the ``inplace`` keyword in :meth:`Categorical.set_ordered`, :meth:`Categorical.as_ordered`, and :meth:`Categorical.as_unordered` (:issue:`37643`)
 - Deprecated setting a categorical's categories with ``cat.categories = ['a', 'b', 'c']``, use :meth:`Categorical.rename_categories` instead (:issue:`37643`)
 - Deprecated unused arguments ``encoding`` and ``verbose`` in :meth:`Series.to_excel` and :meth:`DataFrame.to_excel` (:issue:`47912`)
+- Deprecated the ``inplace`` keyword in :meth:`DataFrame.set_axis` and :meth:`Series.set_axis`, use ``obj = obj.set_axis(..., copy=False)`` instead (:issue:`48130`)
 - Deprecated producing a single element when iterating over a :class:`DataFrameGroupBy` or a :class:`SeriesGroupBy` that has been grouped by a list of length 1; A tuple of length one will be returned instead (:issue:`42795`)
 - Fixed up warning message of deprecation of :meth:`MultiIndex.lesort_depth` as public method, as the message previously referred to :meth:`MultiIndex.is_lexsorted` instead (:issue:`38701`)
 - Deprecated the ``inplace`` keyword in :meth:`DataFrame.set_index`, use ``df = df.set_index(..., copy=False)`` instead (:issue:`48115`)

pandas/core/frame.py

@@ -5061,7 +5061,7 @@ def set_axis(
         labels,
         *,
         axis: Axis = ...,
-        inplace: Literal[False] = ...,
+        inplace: Literal[False] | lib.NoDefault = ...,
         copy: bool | lib.NoDefault = ...,
     ) -> DataFrame:
         ...
@@ -5083,7 +5083,7 @@ def set_axis(
         labels,
         *,
         axis: Axis = ...,
-        inplace: bool = ...,
+        inplace: bool | lib.NoDefault = ...,
         copy: bool | lib.NoDefault = ...,
     ) -> DataFrame | None:
         ...
@@ -5112,10 +5112,9 @@ def set_axis(
         1  2   5
         2  3   6
 
-        Now, update the labels inplace.
+        Now, update the labels without copying the underlying data.
 
-        >>> df.set_axis(['i', 'ii'], axis='columns', inplace=True)
-        >>> df
+        >>> df.set_axis(['i', 'ii'], axis='columns', copy=False)
            i  ii
         0  1   4
         1  2   5
@@ -5133,7 +5132,7 @@ def set_axis(
         self,
         labels,
         axis: Axis = 0,
-        inplace: bool = False,
+        inplace: bool | lib.NoDefault = lib.no_default,
         *,
         copy: bool | lib.NoDefault = lib.no_default,
     ):

pandas/core/generic.py

@@ -715,7 +715,7 @@ def set_axis(
         labels,
         *,
         axis: Axis = ...,
-        inplace: Literal[False] = ...,
+        inplace: Literal[False] | lib.NoDefault = ...,
         copy: bool_t | lib.NoDefault = ...,
     ) -> NDFrameT:
         ...
@@ -737,7 +737,7 @@ def set_axis(
         labels,
         *,
         axis: Axis = ...,
-        inplace: bool_t = ...,
+        inplace: bool_t | lib.NoDefault = ...,
         copy: bool_t | lib.NoDefault = ...,
     ) -> NDFrameT | None:
         ...
@@ -747,7 +747,7 @@ def set_axis(
         self: NDFrameT,
         labels,
         axis: Axis = 0,
-        inplace: bool_t = False,
+        inplace: bool_t | lib.NoDefault = lib.no_default,
         *,
         copy: bool_t | lib.NoDefault = lib.no_default,
     ) -> NDFrameT | None:
@@ -769,6 +769,8 @@ def set_axis(
         inplace : bool, default False
             Whether to return a new %(klass)s instance.
 
+            .. deprecated:: 1.5.0
+
         copy : bool, default True
             Whether to make a copy of the underlying data.
 
@@ -783,6 +785,17 @@ def set_axis(
         --------
         %(klass)s.rename_axis : Alter the name of the index%(see_also_sub)s.
         """
+        if inplace is not lib.no_default:
+            warnings.warn(
+                f"{type(self).__name__}.set_axis 'inplace' keyword is deprecated "
+                "and will be removed in a future version. Use "
+                "`obj = obj.set_axis(..., copy=False)` instead",
+                FutureWarning,
+                stacklevel=find_stack_level(inspect.currentframe()),
+            )
+        else:
+            inplace = False
+
         if inplace:
             if copy is True:
                 raise ValueError("Cannot specify both inplace=True and copy=True")
@@ -795,14 +808,13 @@ def set_axis(
 
     @final
     def _set_axis_nocheck(self, labels, axis: Axis, inplace: bool_t, copy: bool_t):
-        # NDFrame.rename with inplace=False calls set_axis(inplace=True) on a copy.
         if inplace:
             setattr(self, self._get_axis_name(axis), labels)
         else:
             # With copy=False, we create a new object but don't copy the
             #  underlying data.
             obj = self.copy(deep=copy)
-            obj.set_axis(labels, axis=axis, inplace=True)
+            setattr(obj, obj._get_axis_name(axis), labels)
             return obj
 
     def _set_axis(self, axis: int, labels: AnyArrayLike | list) -> None:
@@ -904,7 +916,7 @@ def droplevel(self: NDFrameT, level: IndexLabel, axis: Axis = 0) -> NDFrameT:
         """
         labels = self._get_axis(axis)
         new_labels = labels.droplevel(level)
-        return self.set_axis(new_labels, axis=axis, inplace=False)
+        return self.set_axis(new_labels, axis=axis)
 
     def pop(self, item: Hashable) -> Series | Any:
         result = self[item]
@@ -1363,7 +1375,11 @@ def _set_axis_name(self, name, axis=0, inplace=False):
 
         inplace = validate_bool_kwarg(inplace, "inplace")
         renamed = self if inplace else self.copy()
-        renamed.set_axis(idx, axis=axis, inplace=True)
+        if axis == 0:
+            renamed.index = idx
+        else:
+            renamed.columns = idx
+
         if not inplace:
             return renamed
 
@@ -10205,8 +10221,7 @@ def slice_shift(self: NDFrameT, periods: int = 1, axis=0) -> NDFrameT:
 
         new_obj = self._slice(vslicer, axis=axis)
         shifted_axis = self._get_axis(axis)[islicer]
-        new_obj.set_axis(shifted_axis, axis=axis, inplace=True)
-
+        new_obj = new_obj.set_axis(shifted_axis, axis=axis, copy=False)
         return new_obj.__finalize__(self, method="slice_shift")
 
     @final
@@ -10465,7 +10480,7 @@ def _tz_convert(ax, tz):
             ax = _tz_convert(ax, tz)
 
         result = self.copy(deep=copy)
-        result = result.set_axis(ax, axis=axis, inplace=False)
+        result = result.set_axis(ax, axis=axis, copy=False)
         return result.__finalize__(self, method="tz_convert")
 
     @final
@@ -10635,7 +10650,7 @@ def _tz_localize(ax, tz, ambiguous, nonexistent):
             ax = _tz_localize(ax, tz, ambiguous, nonexistent)
 
         result = self.copy(deep=copy)
-        result = result.set_axis(ax, axis=axis, inplace=False)
+        result = result.set_axis(ax, axis=axis, copy=False)
         return result.__finalize__(self, method="tz_localize")
 
     # ----------------------------------------------------------------------

pandas/core/groupby/groupby.py

@@ -1200,21 +1200,22 @@ def _set_result_index_ordered(
         # set the result index on the passed values object and
         # return the new object, xref 8046
 
+        obj_axis = self.obj._get_axis(self.axis)
+
         if self.grouper.is_monotonic and not self.grouper.has_dropped_na:
             # shortcut if we have an already ordered grouper
-            result.set_axis(self.obj._get_axis(self.axis), axis=self.axis, inplace=True)
+            result = result.set_axis(obj_axis, axis=self.axis, copy=False)
             return result
 
         # row order is scrambled => sort the rows by position in original index
         original_positions = Index(self.grouper.result_ilocs())
-        result.set_axis(original_positions, axis=self.axis, inplace=True)
+        result = result.set_axis(original_positions, axis=self.axis, copy=False)
         result = result.sort_index(axis=self.axis)
-        obj_axis = self.obj._get_axis(self.axis)
         if self.grouper.has_dropped_na:
             # Add back in any missing rows due to dropna - index here is integral
             # with values referring to the row of the input so can use RangeIndex
             result = result.reindex(RangeIndex(len(obj_axis)), axis=self.axis)
-        result.set_axis(obj_axis, axis=self.axis, inplace=True)
+        result = result.set_axis(obj_axis, axis=self.axis, copy=False)
 
         return result
 

pandas/core/series.py

@@ -4980,7 +4980,7 @@ def set_axis(
         labels,
         *,
         axis: Axis = ...,
-        inplace: Literal[False] = ...,
+        inplace: Literal[False] | lib.NoDefault = ...,
         copy: bool | lib.NoDefault = ...,
     ) -> Series:
         ...
@@ -5002,7 +5002,7 @@ def set_axis(
         labels,
         *,
         axis: Axis = ...,
-        inplace: bool = ...,
+        inplace: bool | lib.NoDefault = ...,
         copy: bool | lib.NoDefault = ...,
     ) -> Series | None:
         ...
@@ -5038,7 +5038,7 @@ def set_axis(  # type: ignore[override]
         self,
         labels,
         axis: Axis = 0,
-        inplace: bool = False,
+        inplace: bool | lib.NoDefault = lib.no_default,
         copy: bool | lib.NoDefault = lib.no_default,
     ) -> Series | None:
         return super().set_axis(labels, axis=axis, inplace=inplace, copy=copy)

pandas/tests/frame/methods/test_set_axis.py

@@ -21,7 +21,9 @@ def test_set_axis(self, obj):
         expected.index = new_index
 
         # inplace=False
-        result = obj.set_axis(new_index, axis=0, inplace=False)
+        msg = "set_axis 'inplace' keyword is deprecated"
+        with tm.assert_produces_warning(FutureWarning, match=msg):
+            result = obj.set_axis(new_index, axis=0, inplace=False)
         tm.assert_equal(expected, result)
 
     def test_set_axis_copy(self, obj):
@@ -35,7 +37,8 @@ def test_set_axis_copy(self, obj):
         with pytest.raises(
             ValueError, match="Cannot specify both inplace=True and copy=True"
         ):
-            obj.set_axis(new_index, axis=0, inplace=True, copy=True)
+            with tm.assert_produces_warning(FutureWarning):
+                obj.set_axis(new_index, axis=0, inplace=True, copy=True)
 
         result = obj.set_axis(new_index, axis=0, copy=True)
         tm.assert_equal(expected, result)
@@ -75,7 +78,8 @@ def test_set_axis_copy(self, obj):
             )
 
         # Do this last since it alters obj inplace
-        res = obj.set_axis(new_index, inplace=True, copy=False)
+        with tm.assert_produces_warning(FutureWarning):
+            res = obj.set_axis(new_index, inplace=True, copy=False)
         assert res is None
         tm.assert_equal(expected, obj)
         # check we did NOT make a copy
@@ -103,7 +107,8 @@ def test_set_axis_inplace_axis(self, axis, obj):
             expected.columns = new_index
 
         result = obj.copy()
-        result.set_axis(new_index, axis=axis, inplace=True)
+        with tm.assert_produces_warning(FutureWarning):
+            result.set_axis(new_index, axis=axis, inplace=True)
         tm.assert_equal(result, expected)
 
     def test_set_axis_unnamed_kwarg_warns(self, obj):
@@ -113,7 +118,9 @@ def test_set_axis_unnamed_kwarg_warns(self, obj):
         expected = obj.copy()
         expected.index = new_index
 
-        with tm.assert_produces_warning(None):
+        with tm.assert_produces_warning(
+            FutureWarning, match="set_axis 'inplace' keyword"
+        ):
             result = obj.set_axis(new_index, inplace=False)
         tm.assert_equal(result, expected)
 

pandas/tests/generic/test_duplicate_labels.py

@@ -429,11 +429,19 @@ def test_inplace_raises(method, frame_only):
     s.flags.allows_duplicate_labels = False
     msg = "Cannot specify"
 
+    warn_msg = "Series.set_axis 'inplace' keyword"
+    if "set_axis" in str(method):
+        warn = FutureWarning
+    else:
+        warn = None
+
     with pytest.raises(ValueError, match=msg):
-        method(df)
+        with tm.assert_produces_warning(warn, match=warn_msg):
+            method(df)
     if not frame_only:
         with pytest.raises(ValueError, match=msg):
-            method(s)
+            with tm.assert_produces_warning(warn, match=warn_msg):
+                method(s)
 
 
 def test_pickle():