DEP: Enforce set_values and set_codes inplace and positional args deprecation

doc/source/whatsnew/v2.0.0.rst

@@ -145,6 +145,8 @@ Deprecations
 Removal of prior version deprecations/changes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 - Disallow passing non-round floats to :class:`Timestamp` with ``unit="M"`` or ``unit="Y"`` (:issue:`47266`)
+- Remove argument ``inplace`` from :meth:`MultiIndex.set_levels` and :meth:`MultiIndex.set_codes` (:issue:`35626`)
+- Disallow passing positional arguments to :meth:`MultiIndex.set_levels` and :meth:`MultiIndex.set_codes` (:issue:`41485`)
 - Remove :meth:`DataFrameGroupBy.pad` and :meth:`DataFrameGroupBy.backfill` (:issue:`45076`)
 
 .. ---------------------------------------------------------------------------

pandas/core/indexes/multi.py

@@ -852,10 +852,7 @@ def _set_levels(
 
         self._reset_cache()
 
-    @deprecate_nonkeyword_arguments(version=None, allowed_args=["self", "levels"])
-    def set_levels(
-        self, levels, level=None, inplace=None, verify_integrity: bool = True
-    ):
+    def set_levels(self, levels, *, level=None, verify_integrity: bool = True):
         """
         Set new levels on MultiIndex. Defaults to returning new index.
 
@@ -865,10 +862,6 @@ def set_levels(
             New level(s) to apply.
         level : int, level name, or sequence of int/level names (default None)
             Level(s) to set (None for all levels).
-        inplace : bool
-            If True, mutates in place.
-
-            .. deprecated:: 1.2.0
         verify_integrity : bool, default True
             If True, checks that levels and codes are compatible.
 
@@ -940,30 +933,17 @@ def set_levels(
         >>> idx.set_levels([['a', 'b', 'c'], [1, 2, 3, 4]], level=[0, 1]).levels
         FrozenList([['a', 'b', 'c'], [1, 2, 3, 4]])
         """
-        if inplace is not None:
-            warnings.warn(
-                "inplace is deprecated and will be removed in a future version.",
-                FutureWarning,
-                stacklevel=find_stack_level(),
-            )
-        else:
-            inplace = False
 
         if is_list_like(levels) and not isinstance(levels, Index):
             levels = list(levels)
 
         level, levels = _require_listlike(level, levels, "Levels")
-
-        if inplace:
-            idx = self
-        else:
-            idx = self._view()
+        idx = self._view()
         idx._reset_identity()
         idx._set_levels(
             levels, level=level, validate=True, verify_integrity=verify_integrity
         )
-        if not inplace:
-            return idx
+        return idx
 
     @property
     def nlevels(self) -> int:
@@ -1041,8 +1021,7 @@ def _set_codes(
 
         self._reset_cache()
 
-    @deprecate_nonkeyword_arguments(version=None, allowed_args=["self", "codes"])
-    def set_codes(self, codes, level=None, inplace=None, verify_integrity: bool = True):
+    def set_codes(self, codes, *, level=None, verify_integrity: bool = True):
         """
         Set new codes on MultiIndex. Defaults to returning new index.
 
@@ -1052,10 +1031,6 @@ def set_codes(self, codes, level=None, inplace=None, verify_integrity: bool = Tr
             New codes to apply.
         level : int, level name, or sequence of int/level names (default None)
             Level(s) to set (None for all levels).
-        inplace : bool
-            If True, mutates in place.
-
-            .. deprecated:: 1.2.0
         verify_integrity : bool, default True
             If True, checks that levels and codes are compatible.
 
@@ -1101,25 +1076,12 @@ def set_codes(self, codes, level=None, inplace=None, verify_integrity: bool = Tr
                     (1, 'two')],
                    names=['foo', 'bar'])
         """
-        if inplace is not None:
-            warnings.warn(
-                "inplace is deprecated and will be removed in a future version.",
-                FutureWarning,
-                stacklevel=find_stack_level(),
-            )
-        else:
-            inplace = False
 
         level, codes = _require_listlike(level, codes, "Codes")
-
-        if inplace:
-            idx = self
-        else:
-            idx = self._view()
+        idx = self._view()
         idx._reset_identity()
         idx._set_codes(codes, level=level, verify_integrity=verify_integrity)
-        if not inplace:
-            return idx
+        return idx
 
     # --------------------------------------------------------------------
     # Index Internals

pandas/tests/indexes/multi/test_compat.py

@@ -59,18 +59,12 @@ def test_inplace_mutation_resets_values():
     new_vals = mi1.set_levels(levels2).values
     tm.assert_almost_equal(vals2, new_vals)
 
-    # Non-inplace doesn't drop _values from _cache [implementation detail]
+    #  Doesn't drop _values from _cache [implementation detail]
     tm.assert_almost_equal(mi1._cache["_values"], vals)
 
     # ...and values is still same too
     tm.assert_almost_equal(mi1.values, vals)
 
-    # Inplace should drop _values from _cache
-    with tm.assert_produces_warning(FutureWarning):
-        mi1.set_levels(levels2, inplace=True)
-    assert "_values" not in mi1._cache
-    tm.assert_almost_equal(mi1.values, vals2)
-
     # Make sure label setting works too
     codes2 = [[0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0]]
     exp_values = np.empty((6,), dtype=object)
@@ -84,15 +78,8 @@ def test_inplace_mutation_resets_values():
     new_values = new_mi.values
     assert "_values" in new_mi._cache
 
-    # Not inplace shouldn't change
+    # Shouldn't change cache
     tm.assert_almost_equal(mi2._cache["_values"], vals2)
 
     # Should have correct values
     tm.assert_almost_equal(exp_values, new_values)
-
-    # ...and again setting inplace should drop _values from _cache, etc
-    with tm.assert_produces_warning(FutureWarning):
-        mi2.set_codes(codes2, inplace=True)
-    assert "_values" not in mi2._cache
-    tm.assert_almost_equal(mi2.values, new_values)
-    assert "_values" in mi2._cache

pandas/tests/indexes/multi/test_duplicates.py

@@ -87,8 +87,7 @@ def test_duplicate_multiindex_codes():
     mi = MultiIndex.from_arrays([["A", "A", "B", "B", "B"], [1, 2, 1, 2, 3]])
     msg = r"Level values must be unique: \[[AB', ]+\] on level 0"
     with pytest.raises(ValueError, match=msg):
-        with tm.assert_produces_warning(FutureWarning):
-            mi.set_levels([["A", "B", "A", "A", "B"], [2, 1, 3, -2, 5]], inplace=True)
+        mi.set_levels([["A", "B", "A", "A", "B"], [2, 1, 3, -2, 5]])
 
 
 @pytest.mark.parametrize("names", [["a", "b", "a"], [1, 1, 2], [1, "a", 1]])

pandas/tests/indexes/multi/test_equivalence.py

@@ -243,9 +243,6 @@ def test_is_():
     assert mi.is_(mi2)
 
     assert not mi.is_(mi.set_names(["C", "D"]))
-    mi2 = mi.view()
-    mi2.set_names(["E", "F"], inplace=True)
-    assert mi.is_(mi2)
     # levels are inherent properties, they change identity
     mi3 = mi2.set_levels([list(range(10)), list(range(10))])
     assert not mi3.is_(mi2)
@@ -254,12 +251,10 @@ def test_is_():
     mi4 = mi3.view()
 
     # GH 17464 - Remove duplicate MultiIndex levels
-    with tm.assert_produces_warning(FutureWarning):
-        mi4.set_levels([list(range(10)), list(range(10))], inplace=True)
+    mi4 = mi4.set_levels([list(range(10)), list(range(10))])
     assert not mi4.is_(mi3)
     mi5 = mi.view()
-    with tm.assert_produces_warning(FutureWarning):
-        mi5.set_levels(mi5.levels, inplace=True)
+    mi5 = mi5.set_levels(mi5.levels)
     assert not mi5.is_(mi)