Fixed bug: Dataframe.sort_values not raising ValueError for ascending-incompatible value and Series.sort_values raising ValueError for int value

doc/source/whatsnew/v1.4.0.rst

@@ -224,7 +224,8 @@ Indexing
 - Bug in :meth:`Series.loc` when with a :class:`MultiIndex` whose first level contains only ``np.nan`` values (:issue:`42055`)
 - Bug in indexing on a :class:`Series` or :class:`DataFrame` with a :class:`DatetimeIndex` when passing a string, the return type depended on whether the index was monotonic (:issue:`24892`)
 - Bug in indexing on a :class:`MultiIndex` failing to drop scalar levels when the indexer is a tuple containing a datetime-like string (:issue:`42476`)
--
+- Bug in :meth:`Dataframe.sort_values` when passing a ascending-incompatible value, failed to raise ``ValueError`` (:issue:`41634`)
+- Bug in :meth:`Series.sort_values` when passing a ascending-compatible value; int, raising ``ascending must be boolean`` error (:issue:`41634`)
 
 Missing
 ^^^^^^^

pandas/core/frame.py

@@ -85,6 +85,7 @@
     rewrite_axis_style_signature,
 )
 from pandas.util._validators import (
+    validate_ascending,
     validate_axis_style_args,
     validate_bool_kwarg,
     validate_percentile,
@@ -6190,7 +6191,7 @@ def sort_values(  # type: ignore[override]
     ):
         inplace = validate_bool_kwarg(inplace, "inplace")
         axis = self._get_axis_number(axis)
-
+        ascending = validate_ascending(ascending)
         if not isinstance(by, list):
             by = [by]
         if is_sequence(ascending) and len(by) != len(ascending):

pandas/core/series.py

@@ -57,6 +57,7 @@
     doc,
 )
 from pandas.util._validators import (
+    validate_ascending,
     validate_bool_kwarg,
     validate_percentile,
 )
@@ -69,7 +70,6 @@
 )
 from pandas.core.dtypes.common import (
     ensure_platform_int,
-    is_bool,
     is_dict_like,
     is_integer,
     is_iterator,
@@ -3437,8 +3437,7 @@ def sort_values(
                 )
             ascending = ascending[0]
 
-        if not is_bool(ascending):
-            raise ValueError("ascending must be boolean")
+        ascending = validate_ascending(ascending)
 
         if na_position not in ["first", "last"]:
             raise ValueError(f"invalid na_position: {na_position}")

pandas/tests/frame/methods/test_sort_values.py

@@ -868,3 +868,25 @@ def test_sort_values_pos_args_deprecation(self):
             result = df.sort_values("a", 0)
         expected = DataFrame({"a": [1, 2, 3]})
         tm.assert_frame_equal(result, expected)
+
+    def test_sort_values_validate_ascending(self):
+        # GH41634
+        df = DataFrame({"D": [23, 7, 21]})
+        indexer = df["D"].argsort().values
+        r_indexer = indexer[::-1]
+
+        msg = 'For argument "ascending" expected type bool, received type str.'
+        with pytest.raises(ValueError, match=msg):
+            df.sort_values(by="D", ascending="False")
+
+        expected_df = df.loc[df.index[r_indexer]]
+        sorted_df = df.sort_values(by="D", ascending=False)
+        tm.assert_frame_equal(sorted_df, expected_df)
+
+        expected_df = df.loc[df.index[r_indexer]]
+        sorted_df = df.sort_values(by="D", ascending=0)
+        tm.assert_frame_equal(sorted_df, expected_df)
+
+        expected_df = df.loc[df.index[indexer]]
+        sorted_df = df.sort_values(by="D", ascending=1)
+        tm.assert_frame_equal(sorted_df, expected_df)

pandas/tests/series/methods/test_sort_values.py

@@ -51,7 +51,7 @@ def test_sort_values(self, datetime_series):
         expected = ts.sort_values(ascending=False, na_position="first")
         tm.assert_series_equal(expected, ordered)
 
-        msg = "ascending must be boolean"
+        msg = 'For argument "ascending" expected type bool, received type NoneType.'
         with pytest.raises(ValueError, match=msg):
             ts.sort_values(ascending=None)
         msg = r"Length of ascending \(0\) must be 1 for Series"
@@ -63,7 +63,7 @@ def test_sort_values(self, datetime_series):
         msg = r"Length of ascending \(2\) must be 1 for Series"
         with pytest.raises(ValueError, match=msg):
             ts.sort_values(ascending=[False, False])
-        msg = "ascending must be boolean"
+        msg = 'For argument "ascending" expected type bool, received type str.'
         with pytest.raises(ValueError, match=msg):
             ts.sort_values(ascending="foobar")
 
@@ -206,6 +206,25 @@ def test_mergesort_decending_stability(self):
         expected = Series([3, 2, 1, 1], ["c", "b", "first", "second"])
         tm.assert_series_equal(result, expected)
 
+    def test_sort_values_validate_ascending(self):
+        # GH41634
+        ser = Series([23, 7, 21])
+        expected = np.sort(ser.values)[::-1]
+
+        msg = 'For argument "ascending" expected type bool, received type str.'
+        with pytest.raises(ValueError, match=msg):
+            ser.sort_values(ascending="False")
+
+        sorted_ser = ser.sort_values(ascending=False)
+        tm.assert_numpy_array_equal(sorted_ser.values, expected)
+
+        sorted_ser = ser.sort_values(ascending=0)
+        tm.assert_numpy_array_equal(sorted_ser.values, expected)
+
+        expected = expected[::-1]
+        sorted_ser = ser.sort_values(ascending=1)
+        tm.assert_numpy_array_equal(sorted_ser.values, expected)
+
 
 class TestSeriesSortingKey:
     def test_sort_values_key(self):