Bug in loc raised Error when non-integer slice was given for MultiIndex

doc/source/whatsnew/v1.2.0.rst

@@ -466,6 +466,7 @@ Indexing
 - Bug in indexing on a :class:`Series` or :class:`DataFrame` with a :class:`MultiIndex` with a level named "0" (:issue:`37194`)
 - Bug in :meth:`Series.__getitem__` when using an unsigned integer array as an indexer giving incorrect results or segfaulting instead of raising ``KeyError`` (:issue:`37218`)
 - Bug in :meth:`Index.where` incorrectly casting numeric values to strings (:issue:`37591`)
+- Bug in :meth:`DataFrame.loc` raised ``TypeError`` when non integer interval was given to select values from :class:`MultiIndex` (:issue:`25165`)
 
 Missing
 ^^^^^^^

pandas/core/indexes/multi.py

@@ -2702,7 +2702,10 @@ def _get_loc_single_level_index(self, level_index: Index, key: Hashable) -> int:
         if is_scalar(key) and isna(key):
             return -1
         else:
-            return level_index.get_loc(key)
+            loc = level_index.get_loc(key)
+            # if isinstance(loc, slice):
+            #     return loc.start
+            return loc
 
     def get_loc(self, key, method=None):
         """

pandas/tests/indexing/multiindex/test_loc.py

@@ -598,3 +598,28 @@ def test_getitem_loc_commutability(multiindex_year_month_day_dataframe_random_da
     result = ser[2000, 5]
     expected = df.loc[2000, 5]["A"]
     tm.assert_series_equal(result, expected)
+
+
+def test_getitem_loc_datetime():
+    # GH: 25165
+    date_idx = pd.date_range("2019", periods=2, freq="MS")
+    df = DataFrame(
+        list(range(4)),
+        index=MultiIndex.from_product([date_idx, [0, 1]], names=["x", "y"]),
+    )
+    expected = DataFrame(
+        [2, 3],
+        index=MultiIndex.from_product(
+            [[pd.to_datetime("2019-02-01")], [0, 1]], names=["x", "y"]
+        ),
+    )
+    result = df["2019-2":]
+    tm.assert_frame_equal(result, expected)
+    result = df.loc["2019-2":]
+    tm.assert_frame_equal(result, expected)
+
+    result = df.loc(axis=0)["2019-2":]
+    tm.assert_frame_equal(result, expected)
+
+    result = df.loc["2019-2":, :]
+    tm.assert_frame_equal(result, expected)