BUG: Bug in xs ignored droplevel

doc/source/whatsnew/v1.2.0.rst

@@ -470,6 +470,7 @@ Indexing
 - Bug in :meth:`Index.where` incorrectly casting numeric values to strings (:issue:`37591`)
 - Bug in :meth:`Series.loc` and :meth:`DataFrame.loc` raises when numeric label was given for object :class:`Index` although label was in :class:`Index` (:issue:`26491`)
 - Bug in :meth:`DataFrame.loc` returned requested key plus missing values when ``loc`` was applied to single level from :class:`MultiIndex` (:issue:`27104`)
+- Bug in :meth:`DataFrame.xs` ignored ``droplevel=False`` for columnsm (:issue:`19056`)
 
 Missing
 ^^^^^^^

pandas/core/generic.py

@@ -3708,7 +3708,9 @@ class   animal   locomotion
             return result
 
         if axis == 1:
-            return self[key]
+            if drop_level:
+                return self[key]
+            return self[[key]]
 
         index = self.index
         if isinstance(index, MultiIndex):

pandas/tests/frame/indexing/test_xs.py

@@ -297,3 +297,18 @@ def test_xs_levels_raises(self, klass):
         msg = "Index must be a MultiIndex"
         with pytest.raises(TypeError, match=msg):
             obj.xs(0, level="as")
+
+    def test_xs_droplevel_false(self):
+        # GH: 19056
+        mi = MultiIndex.from_tuples(
+            [("a", "x"), ("a", "y"), ("b", "x")], names=["level1", "level2"]
+        )
+        df = DataFrame([[1, 2, 3]], columns=mi)
+        result = df.xs("a", axis=1, drop_level=False)
+        expected = DataFrame(
+            [[1, 2]],
+            columns=MultiIndex.from_tuples(
+                [("a", "x"), ("a", "y")], names=["level1", "level2"]
+            ),
+        )
+        tm.assert_frame_equal(result, expected)