BUG: PeriodEngine doesn't work (#29038)

Author: proost

doc/source/whatsnew/v1.0.0.rst

@@ -688,6 +688,7 @@ Performance improvements
   The improvement is not present if checking if the :class:`Categorical` is less than or less than or equal than the scalar (:issue:`29820`)
 - Performance improvement in :meth:`Index.equals` and  :meth:`MultiIndex.equals` (:issue:`29134`)
 - Performance improvement in :func:`~pandas.api.types.infer_dtype` when ``skipna`` is ``True`` (:issue:`28814`)
+- Performance improvement in :meth:`PeriodIndex.get_loc` using input from user  (:issue:`29038`)
 
 .. _whatsnew_1000.bug_fixes:
 

pandas/core/indexes/period.py

@@ -642,36 +642,34 @@ def get_loc(self, key, method=None, tolerance=None):
         -------
         loc : int
         """
-        try:
-            return self._engine.get_loc(key)
-        except KeyError:
-            if is_integer(key):
-                raise
-
+        if isinstance(key, str):
             try:
-                asdt, parsed, reso = parse_time_string(key, self.freq)
-                key = asdt
-            except TypeError:
-                pass
+                key, parsed, reso = parse_time_string(key, self.freq)
             except DateParseError:
                 # A string with invalid format
                 raise KeyError(f"Cannot interpret '{key}' as period")
 
-            try:
-                key = Period(key, freq=self.freq)
-            except ValueError:
-                # we cannot construct the Period
-                # as we have an invalid type
-                raise KeyError(key)
+        elif is_integer(key):
+            # Period constructor will cast to string, which we dont want
+            raise KeyError(key)
 
-            try:
-                ordinal = iNaT if key is NaT else key.ordinal
-                if tolerance is not None:
-                    tolerance = self._convert_tolerance(tolerance, np.asarray(key))
-                return self._int64index.get_loc(ordinal, method, tolerance)
+        try:
+            key = Period(key, freq=self.freq)
+            ordinal = key.ordinal if key is not NaT else key.value
+        except ValueError:
+            # we cannot construct the Period
+            # as we have an invalid type
+            if is_list_like(key):
+                raise TypeError(f"'{key}' is an invalid key")
+            raise KeyError(key)
+
+        if tolerance is not None:
+            tolerance = self._convert_tolerance(tolerance, np.asarray(key))
 
-            except KeyError:
-                raise KeyError(key)
+        try:
+            return self._int64index.get_loc(ordinal, method, tolerance)
+        except KeyError:
+            raise KeyError(key)
 
     def _maybe_cast_slice_bound(self, label, side, kind):
         """

pandas/tests/indexes/common.py

@@ -340,7 +340,7 @@ def test_memory_usage(self, indices):
         # RangeIndex, IntervalIndex
         # don't have engines
         if not isinstance(indices, (RangeIndex, IntervalIndex)):
-            assert result2 > result
+            assert result2 >= result
 
         if indices.inferred_type == "object":
             assert result3 > result2