ERR: get_indexer returns the correct indexer when Index is numeric and target is boolean (#16877)

Author: andrejonasson

doc/source/whatsnew/v0.21.0.txt

@@ -481,7 +481,7 @@ Other API Changes
 - :class:`Period` is now immutable, and will now raise an ``AttributeError`` when a user tries to assign a new value to the ``ordinal`` or ``freq`` attributes (:issue:`17116`).
 - :func:`to_datetime` when passed a tz-aware ``origin=`` kwarg will now raise a more informative ``ValueError`` rather than a ``TypeError`` (:issue:`16842`)
 - Renamed non-functional ``index`` to ``index_col`` in :func:`read_stata` to improve API consistency (:issue:`16342`)
-
+- Bug in :func:`DataFrame.drop` caused boolean labels ``False`` and ``True`` to be treated as labels 0 and 1 respectively when dropping indices from a numeric index. This will now raise a ValueError (:issue:`16877`)
 
 .. _whatsnew_0210.deprecations:
 

pandas/core/indexes/base.py

@@ -2609,6 +2609,12 @@ def get_indexer(self, target, method=None, limit=None, tolerance=None):
         if tolerance is not None:
             tolerance = self._convert_tolerance(tolerance)
 
+        # Treat boolean labels passed to a numeric index as not found. Without
+        # this fix False and True would be treated as 0 and 1 respectively.
+        # (GH #16877)
+        if target.is_boolean() and self.is_numeric():
+            return _ensure_platform_int(np.repeat(-1, target.size))
+
         pself, ptarget = self._maybe_promote(target)
         if pself is not self or ptarget is not target:
             return pself.get_indexer(ptarget, method=method, limit=limit,
@@ -2637,7 +2643,6 @@ def get_indexer(self, target, method=None, limit=None, tolerance=None):
                                  'backfill or nearest reindexing')
 
             indexer = self._engine.get_indexer(target._values)
-
         return _ensure_platform_int(indexer)
 
     def _convert_tolerance(self, tolerance):

pandas/tests/indexes/test_base.py

@@ -1141,6 +1141,13 @@ def test_get_indexer_strings(self):
         with pytest.raises(TypeError):
             idx.get_indexer(['a', 'b', 'c', 'd'], method='pad', tolerance=2)
 
+    def test_get_indexer_numeric_index_boolean_target(self):
+        # GH 16877
+        numeric_idx = pd.Index(range(4))
+        result = numeric_idx.get_indexer([True, False, True])
+        expected = np.array([-1, -1, -1], dtype=np.intp)
+        tm.assert_numpy_array_equal(result, expected)
+
     def test_get_loc(self):
         idx = pd.Index([0, 1, 2])
         all_methods = [None, 'pad', 'backfill', 'nearest']

pandas/tests/series/test_indexing.py

@@ -1783,6 +1783,11 @@ def test_drop(self):
         expected = Series([3], index=[False])
         assert_series_equal(result, expected)
 
+        # GH 16877
+        s = Series([2, 3], index=[0, 1])
+        with tm.assert_raises_regex(ValueError, 'not contained in axis'):
+            s.drop([False, True])
+
     def test_align(self):
         def _check_align(a, b, how='left', fill=None):
             aa, ab = a.align(b, join=how, fill_value=fill)