DEPR: NDFrame.set_axis inplace defaults to false #27525

doc/source/whatsnew/v1.0.0.rst

@@ -61,7 +61,7 @@ Deprecations
 Removal of prior version deprecations/changes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 - Removed the previously deprecated :meth:`Series.get_value`, :meth:`Series.set_value`, :meth:`DataFrame.get_value`, :meth:`DataFrame.set_value` (:issue:`17739`)
--
+- Changed the the default value of `inplace` in of :meth:`DataFrame.set_index` and :meth:`Series.set_index`. It now defaults to False (:issue:``)
 -
 
 .. _whatsnew_1000.performance:
@@ -191,6 +191,10 @@ ExtensionArray
 -
 
 
+Other
+^^^^^
+
+
 .. _whatsnew_1000.contributors:
 
 Contributors

pandas/core/generic.py

@@ -564,7 +564,7 @@ def _obj_with_exclusions(self):
         """ internal compat with SelectionMixin """
         return self
 
-    def set_axis(self, labels, axis=0, inplace=None):
+    def set_axis(self, labels, axis=0, inplace=False):
         """
         Assign desired index to given axis.
 
@@ -587,15 +587,9 @@ def set_axis(self, labels, axis=0, inplace=None):
             The axis to update. The value 0 identifies the rows, and 1
             identifies the columns.
 
-        inplace : bool, default None
+        inplace : bool, default False
             Whether to return a new %(klass)s instance.
 
-            .. warning::
-
-               ``inplace=None`` currently falls back to to True, but in a
-               future version, will default to False. Use inplace=True
-               explicitly rather than relying on the default.
-
         Returns
         -------
         renamed : %(klass)s or None
@@ -616,35 +610,27 @@ def set_axis(self, labels, axis=0, inplace=None):
         2    3
         dtype: int64
 
-        >>> s.set_axis(['a', 'b', 'c'], axis=0, inplace=False)
+        >>> s.set_axis(['a', 'b', 'c'], axis=0)
         a    1
         b    2
         c    3
         dtype: int64
 
-        The original object is not modified.
-
-        >>> s
-        0    1
-        1    2
-        2    3
-        dtype: int64
-
         **DataFrame**
 
         >>> df = pd.DataFrame({"A": [1, 2, 3], "B": [4, 5, 6]})
 
         Change the row labels.
 
-        >>> df.set_axis(['a', 'b', 'c'], axis='index', inplace=False)
+        >>> df.set_axis(['a', 'b', 'c'], axis='index')
            A  B
         a  1  4
         b  2  5
         c  3  6
 
         Change the column labels.
 
-        >>> df.set_axis(['I', 'II'], axis='columns', inplace=False)
+        >>> df.set_axis(['I', 'II'], axis='columns')
            I  II
         0  1   4
         1  2   5
@@ -671,14 +657,7 @@ def set_axis(self, labels, axis=0, inplace=None):
             labels, axis = axis, labels
 
         if inplace is None:
-            warnings.warn(
-                "set_axis currently defaults to operating inplace.\nThis "
-                "will change in a future version of pandas, use "
-                "inplace=True to avoid this warning.",
-                FutureWarning,
-                stacklevel=2,
-            )
-            inplace = True
+            raise ValueError("`inplace` cannot have None as a value.")
         if inplace:
             setattr(self, self._get_axis_name(axis), labels)
         else:

pandas/tests/frame/test_alter_axes.py

@@ -1515,30 +1515,23 @@ def test_set_axis_inplace(self):
         expected["columns"] = expected[1]
 
         for axis in expected:
-            # inplace=True
-            # The FutureWarning comes from the fact that we would like to have
-            # inplace default to False some day
-            for inplace, warn in (None, FutureWarning), (True, None):
-                kwargs = {"inplace": inplace}
-
-                result = df.copy()
-                with tm.assert_produces_warning(warn):
-                    result.set_axis(list("abc"), axis=axis, **kwargs)
-                tm.assert_frame_equal(result, expected[axis])
+            result = df.copy()
+            result.set_axis(list("abc"), axis=axis, inplace=True)
+            tm.assert_frame_equal(result, expected[axis])
 
             # inplace=False
-            result = df.set_axis(list("abc"), axis=axis, inplace=False)
+            result = df.set_axis(list("abc"), axis=axis)
             tm.assert_frame_equal(expected[axis], result)
 
         # omitting the "axis" parameter
         with tm.assert_produces_warning(None):
-            result = df.set_axis(list("abc"), inplace=False)
+            result = df.set_axis(list("abc"))
         tm.assert_frame_equal(result, expected[0])
 
         # wrong values for the "axis" parameter
         for axis in 3, "foo":
             with pytest.raises(ValueError, match="No axis named"):
-                df.set_axis(list("abc"), axis=axis, inplace=False)
+                df.set_axis(list("abc"), axis=axis)
 
     def test_set_axis_prior_to_deprecation_signature(self):
         df = DataFrame(

pandas/tests/series/test_alter_axes.py

@@ -277,12 +277,9 @@ def test_set_axis_inplace_axes(self, axis_series):
         # inplace=True
         # The FutureWarning comes from the fact that we would like to have
         # inplace default to False some day
-        for inplace, warn in [(None, FutureWarning), (True, None)]:
-            result = ser.copy()
-            kwargs = {"inplace": inplace}
-            with tm.assert_produces_warning(warn):
-                result.set_axis(list("abcd"), axis=axis_series, **kwargs)
-            tm.assert_series_equal(result, expected)
+        result = ser.copy()
+        result.set_axis(list("abcd"), axis=axis_series, inplace=True)
+        tm.assert_series_equal(result, expected)
 
     def test_set_axis_inplace(self):
         # GH14636