DEPR: deprecate Index.is_boolean (#50176)

Author: topper-123

doc/source/whatsnew/v2.0.0.rst

@@ -573,6 +573,7 @@ Deprecations
 ~~~~~~~~~~~~
 - Deprecated argument ``infer_datetime_format`` in :func:`to_datetime` and :func:`read_csv`, as a strict version of it is now the default (:issue:`48621`)
 - Deprecated :func:`pandas.io.sql.execute`(:issue:`50185`)
+- :meth:`Index.is_boolean` has been deprecated. Use :func:`pandas.api.types.is_bool_dtype` instead (:issue:`50042`)
 - :meth:`Index.is_integer` has been deprecated. Use :func:`pandas.api.types.is_integer_dtype` instead (:issue:`50042`)
 - :meth:`Index.is_floating` has been deprecated. Use :func:`pandas.api.types.is_float_dtype` instead (:issue:`50042`)
 

pandas/core/arrays/categorical.py

@@ -47,6 +47,7 @@
 from pandas.core.dtypes.common import (
     ensure_int64,
     ensure_platform_int,
+    is_bool_dtype,
     is_categorical_dtype,
     is_datetime64_dtype,
     is_dict_like,
@@ -600,7 +601,7 @@ def _from_inferred_categories(
                 cats = to_datetime(inferred_categories, errors="coerce")
             elif is_timedelta64_dtype(dtype.categories):
                 cats = to_timedelta(inferred_categories, errors="coerce")
-            elif dtype.categories.is_boolean():
+            elif is_bool_dtype(dtype.categories):
                 if true_values is None:
                     true_values = ["True", "TRUE", "true"]
 

pandas/core/indexes/base.py

@@ -2192,6 +2192,9 @@ def is_boolean(self) -> bool:
         """
         Check if the Index only consists of booleans.
 
+        .. deprecated:: 2.0.0
+            Use `pandas.api.types.is_bool_dtype` instead.
+
         Returns
         -------
         bool
@@ -2220,6 +2223,12 @@ def is_boolean(self) -> bool:
         >>> idx.is_boolean()
         False
         """
+        warnings.warn(
+            f"{type(self).__name__}.is_boolean is deprecated. "
+            "Use pandas.api.types.is_bool_type instead",
+            FutureWarning,
+            stacklevel=find_stack_level(),
+        )
         return self.inferred_type in ["boolean"]
 
     @final
@@ -2237,7 +2246,7 @@ def is_integer(self) -> bool:
 
         See Also
         --------
-        is_boolean : Check if the Index only consists of booleans.
+        is_boolean : Check if the Index only consists of booleans (deprecated).
         is_floating : Check if the Index is a floating type (deprecated).
         is_numeric : Check if the Index only consists of numeric data.
         is_object : Check if the Index is of the object dtype.
@@ -2285,7 +2294,7 @@ def is_floating(self) -> bool:
 
         See Also
         --------
-        is_boolean : Check if the Index only consists of booleans.
+        is_boolean : Check if the Index only consists of booleans (deprecated).
         is_integer : Check if the Index only consists of integers (deprecated).
         is_numeric : Check if the Index only consists of numeric data.
         is_object : Check if the Index is of the object dtype.
@@ -2330,7 +2339,7 @@ def is_numeric(self) -> bool:
 
         See Also
         --------
-        is_boolean : Check if the Index only consists of booleans.
+        is_boolean : Check if the Index only consists of booleans (deprecated).
         is_integer : Check if the Index only consists of integers (deprecated).
         is_floating : Check if the Index is a floating type (deprecated).
         is_object : Check if the Index is of the object dtype.
@@ -2373,7 +2382,7 @@ def is_object(self) -> bool:
 
         See Also
         --------
-        is_boolean : Check if the Index only consists of booleans.
+        is_boolean : Check if the Index only consists of booleans (deprecated).
         is_integer : Check if the Index only consists of integers (deprecated).
         is_floating : Check if the Index is a floating type (deprecated).
         is_numeric : Check if the Index only consists of numeric data.
@@ -2414,7 +2423,7 @@ def is_categorical(self) -> bool:
         See Also
         --------
         CategoricalIndex : Index for categorical data.
-        is_boolean : Check if the Index only consists of booleans.
+        is_boolean : Check if the Index only consists of booleans (deprecated).
         is_integer : Check if the Index only consists of integers (deprecated).
         is_floating : Check if the Index is a floating type (deprecated).
         is_numeric : Check if the Index only consists of numeric data.
@@ -2457,7 +2466,7 @@ def is_interval(self) -> bool:
         See Also
         --------
         IntervalIndex : Index for Interval objects.
-        is_boolean : Check if the Index only consists of booleans.
+        is_boolean : Check if the Index only consists of booleans (deprecated).
         is_integer : Check if the Index only consists of integers (deprecated).
         is_floating : Check if the Index is a floating type (deprecated).
         is_numeric : Check if the Index only consists of numeric data.
@@ -5874,8 +5883,8 @@ def _should_compare(self, other: Index) -> bool:
         Check if `self == other` can ever have non-False entries.
         """
 
-        if (other.is_boolean() and self.is_numeric()) or (
-            self.is_boolean() and other.is_numeric()
+        if (is_bool_dtype(other) and self.is_numeric()) or (
+            is_bool_dtype(self) and other.is_numeric()
         ):
             # GH#16877 Treat boolean labels passed to a numeric index as not
             #  found. Without this fix False and True would be treated as 0 and 1

pandas/tests/base/common.py

@@ -1,9 +1,10 @@
 from typing import Any
 
 from pandas import Index
+from pandas.api.types import is_bool_dtype
 
 
 def allow_na_ops(obj: Any) -> bool:
     """Whether to skip test cases including NaN"""
-    is_bool_index = isinstance(obj, Index) and obj.is_boolean()
+    is_bool_index = isinstance(obj, Index) and is_bool_dtype(obj)
     return not is_bool_index and obj._can_hold_na

pandas/tests/indexes/common.py

@@ -797,6 +797,12 @@ def test_inv(self, simple_index):
             with pytest.raises(TypeError, match=msg):
                 ~Series(idx)
 
+    def test_is_boolean_is_deprecated(self, simple_index):
+        # GH50042
+        idx = simple_index
+        with tm.assert_produces_warning(FutureWarning):
+            idx.is_boolean()
+
     def test_is_floating_is_deprecated(self, simple_index):
         # GH50042
         idx = simple_index

pandas/tests/indexes/test_setops.py

@@ -25,6 +25,7 @@
 )
 import pandas._testing as tm
 from pandas.api.types import (
+    is_bool_dtype,
     is_datetime64tz_dtype,
     is_signed_integer_dtype,
     pandas_dtype,
@@ -271,7 +272,7 @@ def test_union_base(self, index):
     def test_difference_base(self, sort, index):
         first = index[2:]
         second = index[:4]
-        if index.is_boolean():
+        if is_bool_dtype(index):
             # i think (TODO: be sure) there assumptions baked in about
             #  the index fixture that don't hold here?
             answer = set(first).difference(set(second))

pandas/tests/indexing/test_loc.py

@@ -37,7 +37,10 @@
     to_timedelta,
 )
 import pandas._testing as tm
-from pandas.api.types import is_scalar
+from pandas.api.types import (
+    is_bool_dtype,
+    is_scalar,
+)
 from pandas.core.api import Float64Index
 from pandas.core.indexing import _one_ellipsis_message
 from pandas.tests.indexing.common import check_indexing_smoketest_or_raises
@@ -1658,7 +1661,7 @@ def test_loc_iloc_getitem_leading_ellipses(self, series_with_simple_index, index
         obj = series_with_simple_index
         key = 0 if (indexer is tm.iloc or len(obj) == 0) else obj.index[0]
 
-        if indexer is tm.loc and obj.index.is_boolean():
+        if indexer is tm.loc and is_bool_dtype(obj.index):
             # passing [False] will get interpreted as a boolean mask
             # TODO: should it?  unambiguous when lengths dont match?
             return