BUG: indexing with boolean-like Index, #11119

pandas/core/frame.py

@@ -1941,8 +1941,8 @@ def _getitem_array(self, key):
                 warnings.warn("Boolean Series key will be reindexed to match "
                               "DataFrame index.", UserWarning)
             elif len(key) != len(self.index):
-                raise ValueError('Item wrong length %d instead of %d.' %
-                                 (len(key), len(self.index)))
+                indexer = self.ix._convert_to_indexer(key, axis=1)
+                return self.take(indexer, axis=1, convert=True)
             # check_bool_indexer will throw exception if Series key cannot
             # be reindexed to match DataFrame rows
             key = check_bool_indexer(self.index, key)

pandas/core/indexing.py

@@ -1077,50 +1077,56 @@ def _convert_to_indexer(self, obj, axis=0, is_setter=False):
             return labels.get_locs(obj)
         elif is_list_like_indexer(obj):
             if is_bool_indexer(obj):
-                obj = check_bool_indexer(labels, obj)
-                inds, = obj.nonzero()
-                return inds
-            else:
-                if isinstance(obj, Index):
-                    objarr = obj.values
+                if is_bool_indexer(list(labels)):
+                    pass
+                elif len(obj) == self.obj.shape[axis]:
+                    obj = check_bool_indexer(labels, obj)
+                    inds, = obj.nonzero()
+                    return inds
                 else:
-                    objarr = _asarray_tuplesafe(obj)
+                    raise ValueError('Item wrong length %d instead of %d.' %
+                                 (len(obj), len(self.obj.index)))
+
+            if isinstance(obj, Index):
+                objarr = obj.values
+            else:
+                objarr = _asarray_tuplesafe(obj)
 
-                # The index may want to handle a list indexer differently
-                # by returning an indexer or raising
-                indexer = labels._convert_list_indexer(objarr, kind=self.name)
-                if indexer is not None:
-                    return indexer
+            # The index may want to handle a list indexer differently
+            # by returning an indexer or raising
+            indexer = labels._convert_list_indexer(objarr, kind=self.name)
+            if indexer is not None:
+                return indexer
 
-                # this is not the most robust, but...
-                if (isinstance(labels, MultiIndex) and
-                        not isinstance(objarr[0], tuple)):
-                    level = 0
-                    _, indexer = labels.reindex(objarr, level=level)
+            # this is not the most robust, but...
+            if (isinstance(labels, MultiIndex) and
+                    not isinstance(objarr[0], tuple)):
+                level = 0
+                _, indexer = labels.reindex(objarr, level=level)
 
-                    # take all
-                    if indexer is None:
-                        indexer = np.arange(len(labels))
+                # take all
+                if indexer is None:
+                    indexer = np.arange(len(labels))
 
-                    check = labels.levels[0].get_indexer(objarr)
-                else:
-                    level = None
+                check = labels.levels[0].get_indexer(objarr)
+            else:
+                level = None
 
-                    # unique index
-                    if labels.is_unique:
-                        indexer = check = labels.get_indexer(objarr)
+                # unique index
+                if labels.is_unique:
+                    indexer = check = labels.get_indexer(objarr)
 
-                    # non-unique (dups)
-                    else:
-                        (indexer,
-                         missing) = labels.get_indexer_non_unique(objarr)
-                        check = indexer
+                # non-unique (dups)
+                else:
+                    (indexer,
+                     missing) = labels.get_indexer_non_unique(objarr)
+                    check = indexer
 
-                mask = check == -1
-                if mask.any():
-                    raise KeyError('%s not in index' % objarr[mask])
+            mask = check == -1
+            if mask.any():
+                raise KeyError('%s not in index' % objarr[mask])
 
-                return _values_from_object(indexer)
+            return _values_from_object(indexer)
 
         else:
             try:

pandas/tests/test_index.py

@@ -943,6 +943,12 @@ def test_booleanindex(self):
         subIndex = self.strIndex[list(boolIdx)]
         for i, val in enumerate(subIndex):
             self.assertEqual(subIndex.get_loc(val), i)
+
+    def test_booleanLabel(self):
+        df = pd.DataFrame({True: [1,2,5,9],
+                            False: [6,1,13,8]})
+        self.assert_frame_equal(df[df[True]>3], df[2:])
+        self.assert_frame_equal(df[[False,True]], df)
 
     def test_fancy(self):
         sl = self.strIndex[[1, 2, 3]]