Fixed apply_index

Closes pandas-dev#34580

Author: TomAugspurger

doc/source/whatsnew/v1.1.0.rst

@@ -811,6 +811,7 @@ Deprecations
 - :meth:`DatetimeIndex.week` and `DatetimeIndex.weekofyear` are deprecated and will be removed in a future version, use :meth:`DatetimeIndex.isocalendar().week` instead (:issue:`33595`)
 - :meth:`DatetimeArray.week` and `DatetimeArray.weekofyear` are deprecated and will be removed in a future version, use :meth:`DatetimeArray.isocalendar().week` instead (:issue:`33595`)
 - :meth:`DateOffset.__call__` is deprecated and will be removed in a future version, use ``offset + other`` instead (:issue:`34171`)
+- :meth:`~BusinessDay.apply_index` is deprecated and will be removed in a  future version. Use ``offset + other`` instead (:issue:`34580`)
 - :meth:`DataFrame.tshift` and :meth:`Series.tshift` are deprecated and will be removed in a future version, use :meth:`DataFrame.shift` and :meth:`Series.shift` instead (:issue:`11631`)
 - Indexing an :class:`Index` object with a float key is deprecated, and will
   raise an ``IndexError`` in the future. You can manually convert to an integer key

pandas/_libs/tslibs/offsets.pyx

@@ -82,17 +82,45 @@ cdef bint _is_normalized(datetime dt):
     return True
 
 
+def apply_wrapper_core(func, self, other):
+    result = func(self, other)
+    result = np.asarray(result)
+
+    if self.normalize:
+        result = normalize_i8_timestamps(result.view("i8"), None)
+
+    return result
+
+
 def apply_index_wraps(func):
     # Note: normally we would use `@functools.wraps(func)`, but this does
     # not play nicely with cython class methods
-    def wrapper(self, other) -> np.ndarray:
+    def wrapper(self, other):
         # other is a DatetimeArray
+        result = apply_wrapper_core(func, self, other)
+        result = type(other)(result)
+        warnings.warn("'Offset.apply_index(other)' is deprecated. "
+                      "Use 'offset + other' instead.", FutureWarning)
+        return result
 
-        result = func(self, other)
-        result = np.asarray(result)
+    # do @functools.wraps(func) manually since it doesn't work on cdef funcs
+    wrapper.__name__ = func.__name__
+    wrapper.__doc__ = func.__doc__
+    try:
+        wrapper.__module__ = func.__module__
+    except AttributeError:
+        # AttributeError: 'method_descriptor' object has no
+        # attribute '__module__'
+        pass
+    return wrapper
 
-        if self.normalize:
-            result = normalize_i8_timestamps(result.view("i8"), None)
+
+def apply_array_wraps(func):
+    # Note: normally we would use `@functools.wraps(func)`, but this does
+    # not play nicely with cython class methods
+    def wrapper(self, other) -> np.ndarray:
+        # other is a DatetimeArray
+        result = apply_wrapper_core(func, self, other)
         return result
 
     # do @functools.wraps(func) manually since it doesn't work on cdef funcs
@@ -554,6 +582,10 @@ cdef class BaseOffset:
         raises NotImplementedError for offsets without a
         vectorized implementation.
 
+        .. deprecated:: 1.1.0
+
+           Use ``offset + dtindex`` instead.
+
         Parameters
         ----------
         index : DatetimeIndex
@@ -567,6 +599,13 @@ cdef class BaseOffset:
             "does not have a vectorized implementation"
         )
 
+    @apply_array_wraps
+    def _apply_array(self, dtindex):
+        raise NotImplementedError(
+            f"DateOffset subclass {type(self).__name__} "
+            "does not have a vectorized implementation"
+        )
+
     def rollback(self, dt) -> datetime:
         """
         Roll provided date backward to next offset only if not on offset.
@@ -1031,6 +1070,10 @@ cdef class RelativeDeltaOffset(BaseOffset):
         -------
         ndarray[datetime64[ns]]
         """
+        return self._apply_array(dtindex)
+
+    @apply_array_wraps
+    def _apply_array(self, dtindex):
         dt64other = np.asarray(dtindex)
         kwds = self.kwds
         relativedelta_fast = {
@@ -1360,6 +1403,10 @@ cdef class BusinessDay(BusinessMixin):
 
     @apply_index_wraps
     def apply_index(self, dtindex):
+        return self._apply_array(dtindex)
+
+    @apply_array_wraps
+    def _apply_array(self, dtindex):
         i8other = dtindex.view("i8")
         return shift_bdays(i8other, self.n)
 
@@ -1843,6 +1890,10 @@ cdef class YearOffset(SingleConstructorOffset):
 
     @apply_index_wraps
     def apply_index(self, dtindex):
+        return self._apply_array(dtindex)
+
+    @apply_array_wraps
+    def _apply_array(self, dtindex):
         shifted = shift_quarters(
             dtindex.view("i8"), self.n, self.month, self._day_opt, modby=12
         )
@@ -1996,6 +2047,10 @@ cdef class QuarterOffset(SingleConstructorOffset):
 
     @apply_index_wraps
     def apply_index(self, dtindex):
+        return self._apply_array(dtindex)
+
+    @apply_array_wraps
+    def _apply_array(self, dtindex):
         shifted = shift_quarters(
             dtindex.view("i8"), self.n, self.startingMonth, self._day_opt
         )
@@ -2111,6 +2166,10 @@ cdef class MonthOffset(SingleConstructorOffset):
 
     @apply_index_wraps
     def apply_index(self, dtindex):
+        return self._apply_array(dtindex)
+
+    @apply_array_wraps
+    def _apply_array(self, dtindex):
         shifted = shift_months(dtindex.view("i8"), self.n, self._day_opt)
         return shifted
 
@@ -2248,6 +2307,12 @@ cdef class SemiMonthOffset(SingleConstructorOffset):
     @cython.wraparound(False)
     @cython.boundscheck(False)
     def apply_index(self, dtindex):
+        return self._apply_array(dtindex)
+
+    @apply_array_wraps
+    @cython.wraparound(False)
+    @cython.boundscheck(False)
+    def _apply_array(self, dtindex):
         cdef:
             int64_t[:] i8other = dtindex.view("i8")
             Py_ssize_t i, count = len(i8other)
@@ -2407,6 +2472,10 @@ cdef class Week(SingleConstructorOffset):
 
     @apply_index_wraps
     def apply_index(self, dtindex):
+        return self._apply_array(dtindex)
+
+    @apply_array_wraps
+    def _apply_array(self, dtindex):
         if self.weekday is None:
             td = timedelta(days=7 * self.n)
             td64 = np.timedelta64(td, "ns")
@@ -3185,6 +3254,9 @@ cdef class CustomBusinessDay(BusinessDay):
     def apply_index(self, dtindex):
         raise NotImplementedError
 
+    def _apply_array(self, dtindex):
+        raise NotImplementedError
+
     def is_on_offset(self, dt: datetime) -> bool:
         if self.normalize and not _is_normalized(dt):
             return False

pandas/core/arrays/datetimes.py

@@ -679,7 +679,7 @@ def _add_offset(self, offset):
                 values = self.tz_localize(None)
             else:
                 values = self
-            result = offset.apply_index(values)
+            result = offset._apply_array(values)
             result = DatetimeArray._simple_new(result)
             result = result.tz_localize(self.tz)
 

pandas/tests/tseries/offsets/test_offsets.py

@@ -3673,6 +3673,28 @@ def test_apply_index(self, case):
         exp = DatetimeIndex(cases.values())
         tm.assert_index_equal(result, exp)
 
+    @pytest.mark.parametrize(
+        "offset",
+        [
+            offsets.YearEnd(),
+            offsets.YearBegin(),
+            offsets.QuarterEnd(),
+            offsets.QuarterBegin(),
+            offsets.MonthEnd(),
+            offsets.MonthBegin(),
+            offsets.DateOffset(months=2, days=2),
+            offsets.BusinessDay(),
+            offsets.SemiMonthEnd(),
+            offsets.SemiMonthBegin(),
+        ],
+    )
+    def test_apply_index_2(self, offset):
+        # https://github.com/pandas-dev/pandas/issues/34580
+        rng = date_range(start="1/1/2000", periods=10, freq="T")
+        with tm.assert_produces_warning(FutureWarning):
+            result = offset.apply_index(rng)
+        assert isinstance(result, DatetimeIndex)
+
     on_offset_cases = [
         (datetime(2007, 12, 31), True),
         (datetime(2007, 12, 15), True),