PERF: Avoid materializing values for PeriodIndex shape, size

Author: TomAugspurger

pandas/core/indexes/period.py

@@ -477,6 +477,16 @@ def _to_embed(self, keep_tz=False, dtype=None):
 
         return self.astype(object).values
 
+    @property
+    def size(self):
+        # Avoid materializing self._values
+        return self._ndarray_values.size
+
+    @property
+    def shape(self):
+        # Avoid materializing self._values
+        return self._ndarray_values.shape
+
     @property
     def _formatter_func(self):
         return lambda x: "'%s'" % x