More speedups for Period comparisons (#21606)

Author: jbrockmendel

doc/source/whatsnew/v0.24.0.txt

@@ -135,7 +135,7 @@ Performance Improvements
 
 - Improved performance of :func:`Series.describe` in case of numeric dtpyes (:issue:`21274`)
 - Improved performance of :func:`pandas.core.groupby.GroupBy.rank` when dealing with tied rankings (:issue:`21237`)
-- Improved performance of :func:`DataFrame.set_index` with columns consisting of :class:`Period` objects (:issue:`21582`)
+- Improved performance of :func:`DataFrame.set_index` with columns consisting of :class:`Period` objects (:issue:`21582`,:issue:`21606`)
 -
 
 .. _whatsnew_0240.docs:

pandas/_libs/tslibs/offsets.pyx

@@ -88,6 +88,15 @@ for _d in DAYS:
 # ---------------------------------------------------------------------
 # Misc Helpers
 
+cdef to_offset(object obj):
+ """
+ Wrap pandas.tseries.frequencies.to_offset to keep centralize runtime
+ imports
+ """
+ from pandas.tseries.frequencies import to_offset
+ return to_offset(obj)
+
+
 def as_datetime(obj):
  f = getattr(obj, 'to_pydatetime', None)
  if f is not None:
@@ -313,6 +322,41 @@ class _BaseOffset(object):
  def __setattr__(self, name, value):
  raise AttributeError("DateOffset objects are immutable.")
 
+ def __eq__(self, other):
+ if is_string_object(other):
+ other = to_offset(other)
+
+ try:
+ return self._params == other._params
+ except AttributeError:
+ # other is not a DateOffset object
+ return False
+
+ return self._params == other._params
+
+ def __ne__(self, other):
+ return not self == other
+
+ def __hash__(self):
+ return hash(self._params)
+
+ @property
+ def _params(self):
+ """
+ Returns a tuple containing all of the attributes needed to evaluate
+ equality between two DateOffset objects.
+ """
+ # NB: non-cython subclasses override property with cache_readonly
+ all_paras = self.__dict__.copy()
+ if 'holidays' in all_paras and not all_paras['holidays']:
+ all_paras.pop('holidays')
+ exclude = ['kwds', 'name', 'calendar']
+ attrs = [(k, v) for k, v in all_paras.items()
+ if (k not in exclude) and (k[0] != '_')]
+ attrs = sorted(set(attrs))
+ params = tuple([str(self.__class__)] + attrs)
+ return params
+
  @property
  def kwds(self):
  # for backwards-compatibility

pandas/tseries/offsets.py

@@ -182,6 +182,7 @@ def __add__(date):
 
  Since 0 is a bit weird, we suggest avoiding its use.
  """
+ _params = cache_readonly(BaseOffset._params.fget)
  _use_relativedelta = False
  _adjust_dst = False
  _attributes = frozenset(['n', 'normalize'] +
@@ -288,18 +289,6 @@ def isAnchored(self):
  # if there were a canonical docstring for what isAnchored means.
  return (self.n == 1)
 
- @cache_readonly
- def _params(self):
- all_paras = self.__dict__.copy()
- if 'holidays' in all_paras and not all_paras['holidays']:
- all_paras.pop('holidays')
- exclude = ['kwds', 'name', 'calendar']
- attrs = [(k, v) for k, v in all_paras.items()
- if (k not in exclude) and (k[0] != '_')]
- attrs = sorted(set(attrs))
- params = tuple([str(self.__class__)] + attrs)
- return params
-
  # TODO: Combine this with BusinessMixin version by defining a whitelisted
  # set of attributes on each object rather than the existing behavior of
  # iterating over internal ``__dict__``
@@ -322,24 +311,6 @@ def _repr_attrs(self):
  def name(self):
  return self.rule_code
 
- def __eq__(self, other):
-
- if isinstance(other, compat.string_types):
- from pandas.tseries.frequencies import to_offset
-
- other = to_offset(other)
-
- if not isinstance(other, DateOffset):
- return False
-
- return self._params == other._params
-
- def __ne__(self, other):
- return not self == other
-
- def __hash__(self):
- return hash(self._params)
-
  def __add__(self, other):
  if isinstance(other, (ABCDatetimeIndex, ABCSeries)):
  return other + self