_new_PeriodIndex for unpickling

Author: max-sixty

pandas/indexes/base.py

@@ -89,9 +89,8 @@ def _new_Index(cls, d):
     # required for backward compat, because PI can't be instantiated with
     # ordinals through __new__ GH #13277
     if issubclass(cls, ABCPeriodIndex):
-        if d['data'].dtype == 'int64':
-            values = d.pop('data')
-            return cls._from_ordinals(values=values, **d)
+        from pandas.tseries.period import _new_PeriodIndex
+        return _new_PeriodIndex(cls, **d)
     return cls.__new__(cls, **d)
 
 

pandas/tseries/period.py

@@ -109,6 +109,13 @@ def wrapper(self, other):
     return wrapper
 
 
+def _new_PeriodIndex(cls, **d):
+    # GH13277 for unpickling
+    if d['data'].dtype == 'int64':
+        values = d.pop('data')
+    return cls._from_ordinals(values=values, **d)
+
+
 class PeriodIndex(DatelikeOps, DatetimeIndexOpsMixin, Int64Index):
     """
     Immutable ndarray holding ordinal values indicating regular periods in
@@ -204,9 +211,9 @@ def __new__(cls, data=None, ordinal=None, freq=None, start=None, end=None,
                 msg = 'specified freq and dtype are different'
                 raise IncompatibleFrequency(msg)
 
-        # coerce freq to freq object, otherwise it can be coorced elementwise
+        # coerce freq to freq object, otherwise it can be coerced elementwise
         # which is slow
-        if freq is not None:
+        if freq:
             freq = Period._maybe_convert_freq(freq)
 
         if data is None: