DEPR: enforce non-positional, keyword deprecations (#49507)

Author: jbrockmendel

doc/source/whatsnew/v2.0.0.rst

@@ -295,6 +295,8 @@ Removal of prior version deprecations/changes
 - Removed ``keep_tz`` argument in :meth:`DatetimeIndex.to_series` (:issue:`29731`)
 - Remove arguments ``names`` and ``dtype`` from :meth:`Index.copy` and ``levels`` and ``codes`` from :meth:`MultiIndex.copy` (:issue:`35853`, :issue:`36685`)
 - Remove argument ``inplace`` from :meth:`MultiIndex.set_levels` and :meth:`MultiIndex.set_codes` (:issue:`35626`)
+- Removed arguments ``verbose`` and ``encoding`` from :meth:`DataFrame.to_excel` and :meth:`Series.to_excel` (:issue:`47912`)
+- Removed argument ``line_terminator`` from :meth:`DataFrame.to_csv` and :meth:`Series.to_csv`, use ``lineterminator`` instead (:issue:`45302`)
 - Removed argument ``inplace`` from :meth:`DataFrame.set_axis` and :meth:`Series.set_axis`, use ``obj = obj.set_axis(..., copy=False)`` instead (:issue:`48130`)
 - Disallow passing positional arguments to :meth:`MultiIndex.set_levels` and :meth:`MultiIndex.set_codes` (:issue:`41485`)
 - Removed :meth:`MultiIndex.is_lexsorted` and :meth:`MultiIndex.lexsort_depth` (:issue:`38701`)
@@ -312,6 +314,8 @@ Removal of prior version deprecations/changes
 - Remove keywords ``convert_float`` and ``mangle_dupe_cols`` from :func:`read_excel` (:issue:`41176`)
 - Removed ``errors`` keyword from :meth:`DataFrame.where`, :meth:`Series.where`, :meth:`DataFrame.mask` and :meth:`Series.mask` (:issue:`47728`)
 - Disallow passing non-keyword arguments to :func:`read_excel` except ``io`` and ``sheet_name`` (:issue:`34418`)
+- Disallow passing non-keyword arguments to :meth:`DataFrame.drop` and :meth:`Series.drop` except ``labels`` (:issue:`41486`)
+- Disallow passing non-keyword arguments to :meth:`DataFrame.fillna` and :meth:`Series.fillna` except ``value`` (:issue:`41485`)
 - Disallow passing non-keyword arguments to :meth:`StringMethods.split` and :meth:`StringMethods.rsplit` except for ``pat`` (:issue:`47448`)
 - Disallow passing non-keyword arguments to :meth:`DataFrame.set_index` except ``keys`` (:issue:`41495`)
 - Disallow passing non-keyword arguments to :meth:`Resampler.interpolate` except ``method`` (:issue:`41699`)

pandas/core/frame.py

@@ -5156,12 +5156,10 @@ def drop(
     ) -> DataFrame | None:
         ...
 
-    # error: Signature of "drop" incompatible with supertype "NDFrame"
-    # github.com/python/mypy/issues/12387
-    @deprecate_nonkeyword_arguments(version=None, allowed_args=["self", "labels"])
-    def drop(  # type: ignore[override]
+    def drop(
         self,
         labels: IndexLabel = None,
+        *,
         axis: Axis = 0,
         index: IndexLabel = None,
         columns: IndexLabel = None,
@@ -5531,11 +5529,11 @@ def fillna(
         ...
 
     # error: Signature of "fillna" incompatible with supertype "NDFrame"
-    @deprecate_nonkeyword_arguments(version=None, allowed_args=["self", "value"])
     @doc(NDFrame.fillna, **_shared_doc_kwargs)
     def fillna(  # type: ignore[override]
         self,
         value: Hashable | Mapping | Series | DataFrame = None,
+        *,
         method: FillnaOptions | None = None,
         axis: Axis | None = None,
         inplace: bool = False,

pandas/core/generic.py

@@ -86,8 +86,6 @@
     SettingWithCopyWarning,
 )
 from pandas.util._decorators import (
-    deprecate_kwarg,
-    deprecate_nonkeyword_arguments,
     doc,
     rewrite_axis_style_signature,
 )
@@ -2130,8 +2128,6 @@ def _repr_data_resource_(self):
     # I/O Methods
 
     @final
-    @deprecate_kwarg(old_arg_name="verbose", new_arg_name=None)
-    @deprecate_kwarg(old_arg_name="encoding", new_arg_name=None)
     @doc(
         klass="object",
         storage_options=_shared_docs["storage_options"],
@@ -2151,9 +2147,7 @@ def to_excel(
         startcol: int = 0,
         engine: str | None = None,
         merge_cells: bool_t = True,
-        encoding: lib.NoDefault = lib.no_default,
         inf_rep: str = "inf",
-        verbose: lib.NoDefault = lib.no_default,
         freeze_panes: tuple[int, int] | None = None,
         storage_options: StorageOptions = None,
     ) -> None:
@@ -2203,24 +2197,9 @@ def to_excel(
 
         merge_cells : bool, default True
             Write MultiIndex and Hierarchical Rows as merged cells.
-        encoding : str, optional
-            Encoding of the resulting excel file. Only necessary for xlwt,
-            other writers support unicode natively.
-
-            .. deprecated:: 1.5.0
-
-                This keyword was not used.
-
         inf_rep : str, default 'inf'
             Representation for infinity (there is no native representation for
             infinity in Excel).
-        verbose : bool, default True
-            Display more information in the error logs.
-
-            .. deprecated:: 1.5.0
-
-                This keyword was not used.
-
         freeze_panes : tuple of int (length 2), optional
             Specifies the one-based bottommost row and rightmost column that
             is to be frozen.
@@ -3469,7 +3448,6 @@ def to_csv(
         storage_options=_shared_docs["storage_options"],
         compression_options=_shared_docs["compression_options"] % "path_or_buf",
     )
-    @deprecate_kwarg(old_arg_name="line_terminator", new_arg_name="lineterminator")
     def to_csv(
         self,
         path_or_buf: FilePath | WriteBuffer[bytes] | WriteBuffer[str] | None = None,
@@ -4394,10 +4372,10 @@ def drop(
     ) -> NDFrameT | None:
         ...
 
-    @deprecate_nonkeyword_arguments(version=None, allowed_args=["self", "labels"])
     def drop(
         self: NDFrameT,
         labels: IndexLabel = None,
+        *,
         axis: Axis = 0,
         index: IndexLabel = None,
         columns: IndexLabel = None,

pandas/core/series.py

@@ -67,7 +67,6 @@
 from pandas.util._decorators import (
     Appender,
     Substitution,
-    deprecate_nonkeyword_arguments,
     doc,
 )
 from pandas.util._exceptions import find_stack_level
@@ -5021,12 +5020,10 @@ def drop(
     ) -> Series | None:
         ...
 
-    # error: Signature of "drop" incompatible with supertype "NDFrame"
-    # github.com/python/mypy/issues/12387
-    @deprecate_nonkeyword_arguments(version=None, allowed_args=["self", "labels"])
-    def drop(  # type: ignore[override]
+    def drop(
         self,
         labels: IndexLabel = None,
+        *,
         axis: Axis = 0,
         index: IndexLabel = None,
         columns: IndexLabel = None,
@@ -5170,11 +5167,11 @@ def fillna(
         ...
 
     #  error: Signature of "fillna" incompatible with supertype "NDFrame"
-    @deprecate_nonkeyword_arguments(version=None, allowed_args=["self", "value"])
     @doc(NDFrame.fillna, **_shared_doc_kwargs)
     def fillna(  # type: ignore[override]
         self,
         value: Hashable | Mapping | Series | DataFrame = None,
+        *,
         method: FillnaOptions | None = None,
         axis: Axis | None = None,
         inplace: bool = False,

pandas/tests/frame/methods/test_fillna.py

@@ -611,18 +611,6 @@ def test_fillna_downcast_dict(self):
         expected = DataFrame({"col1": [1, 2]})
         tm.assert_frame_equal(result, expected)
 
-    def test_fillna_pos_args_deprecation(self):
-        # https://github.com/pandas-dev/pandas/issues/41485
-        df = DataFrame({"a": [1, 2, 3, np.nan]}, dtype=float)
-        msg = (
-            r"In a future version of pandas all arguments of DataFrame.fillna "
-            r"except for the argument 'value' will be keyword-only"
-        )
-        with tm.assert_produces_warning(FutureWarning, match=msg):
-            result = df.fillna(0, None, None)
-        expected = DataFrame({"a": [1, 2, 3, 0]}, dtype=float)
-        tm.assert_frame_equal(result, expected)
-
     def test_fillna_with_columns_and_limit(self):
         # GH40989
         df = DataFrame(

pandas/tests/io/formats/test_to_csv.py

@@ -388,9 +388,7 @@ def test_to_csv_single_level_multi_index(self, ind, expected, frame_or_series):
         # see gh-19589
         obj = frame_or_series(pd.Series([1], ind, name="data"))
 
-        with tm.assert_produces_warning(FutureWarning, match="lineterminator"):
-            # GH#9568 standardize on lineterminator matching stdlib
-            result = obj.to_csv(line_terminator="\n", header=True)
+        result = obj.to_csv(lineterminator="\n", header=True)
         assert result == expected
 
     def test_to_csv_string_array_ascii(self):

pandas/tests/series/methods/test_drop.py

@@ -90,19 +90,6 @@ def test_drop_non_empty_list(data, index, drop_labels):
         ser.drop(drop_labels)
 
 
-def test_drop_pos_args_deprecation():
-    # https://github.com/pandas-dev/pandas/issues/41485
-    ser = Series([1, 2, 3])
-    msg = (
-        r"In a future version of pandas all arguments of Series\.drop "
-        r"except for the argument 'labels' will be keyword-only"
-    )
-    with tm.assert_produces_warning(FutureWarning, match=msg):
-        result = ser.drop(1, 0)
-    expected = Series([1, 3], index=[0, 2])
-    tm.assert_series_equal(result, expected)
-
-
 def test_drop_index_ea_dtype(any_numeric_ea_dtype):
     # GH#45860
     df = Series(100, index=Index([1, 2, 2], dtype=any_numeric_ea_dtype))

pandas/tests/series/methods/test_fillna.py

@@ -828,18 +828,6 @@ def test_fillna_datetime64_with_timezone_tzinfo(self):
         )
         tm.assert_series_equal(result, expected)
 
-    def test_fillna_pos_args_deprecation(self):
-        # https://github.com/pandas-dev/pandas/issues/41485
-        srs = Series([1, 2, 3, np.nan], dtype=float)
-        msg = (
-            r"In a future version of pandas all arguments of Series.fillna "
-            r"except for the argument 'value' will be keyword-only"
-        )
-        with tm.assert_produces_warning(FutureWarning, match=msg):
-            result = srs.fillna(0, None, None)
-        expected = Series([1, 2, 3, 0], dtype=float)
-        tm.assert_series_equal(result, expected)
-
     @pytest.mark.parametrize(
         "input, input_fillna, expected_data, expected_categories",
         [