ENH: DatetimeArray fields support non-nano (#47044)

Author: jbrockmendel

pandas/_libs/tslibs/fields.pyi

@@ -22,6 +22,7 @@ def get_start_end_field(
 def get_date_field(
     dtindex: npt.NDArray[np.int64],  # const int64_t[:]
     field: str,
+    reso: int = ...,  # NPY_DATETIMEUNIT
 ) -> npt.NDArray[np.int32]: ...
 def get_timedelta_field(
     tdindex: npt.NDArray[np.int64],  # const int64_t[:]
@@ -32,6 +33,7 @@ def isleapyear_arr(
 ) -> npt.NDArray[np.bool_]: ...
 def build_isocalendar_sarray(
     dtindex: npt.NDArray[np.int64],  # const int64_t[:]
+    reso: int = ...,  # NPY_DATETIMEUNIT
 ) -> np.ndarray: ...
 def _get_locale_names(name_type: str, locale: str | None = ...): ...
 

pandas/_libs/tslibs/fields.pyx

@@ -329,7 +329,7 @@ def get_start_end_field(
 
 @cython.wraparound(False)
 @cython.boundscheck(False)
-def get_date_field(const int64_t[:] dtindex, str field):
+def get_date_field(const int64_t[:] dtindex, str field, NPY_DATETIMEUNIT reso=NPY_FR_ns):
     """
     Given a int64-based datetime index, extract the year, month, etc.,
     field and return an array of these values.
@@ -348,7 +348,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = dts.year
         return out
 
@@ -359,7 +359,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = dts.month
         return out
 
@@ -370,7 +370,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = dts.day
         return out
 
@@ -381,8 +381,9 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = dts.hour
+                # TODO: can we de-dup with period.pyx <accessor>s?
         return out
 
     elif field == 'm':
@@ -392,7 +393,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = dts.min
         return out
 
@@ -403,7 +404,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = dts.sec
         return out
 
@@ -414,7 +415,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = dts.us
         return out
 
@@ -425,7 +426,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = dts.ps // 1000
         return out
     elif field == 'doy':
@@ -435,7 +436,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = get_day_of_year(dts.year, dts.month, dts.day)
         return out
 
@@ -446,7 +447,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = dayofweek(dts.year, dts.month, dts.day)
         return out
 
@@ -457,7 +458,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = get_week_of_year(dts.year, dts.month, dts.day)
         return out
 
@@ -468,7 +469,7 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = dts.month
                 out[i] = ((out[i] - 1) // 3) + 1
         return out
@@ -480,11 +481,11 @@ def get_date_field(const int64_t[:] dtindex, str field):
                     out[i] = -1
                     continue
 
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 out[i] = get_days_in_month(dts.year, dts.month)
         return out
     elif field == 'is_leap_year':
-        return isleapyear_arr(get_date_field(dtindex, 'Y'))
+        return isleapyear_arr(get_date_field(dtindex, 'Y', reso=reso))
 
     raise ValueError(f"Field {field} not supported")
 
@@ -564,7 +565,7 @@ cpdef isleapyear_arr(ndarray years):
 
 @cython.wraparound(False)
 @cython.boundscheck(False)
-def build_isocalendar_sarray(const int64_t[:] dtindex):
+def build_isocalendar_sarray(const int64_t[:] dtindex, NPY_DATETIMEUNIT reso=NPY_FR_ns):
     """
     Given a int64-based datetime array, return the ISO 8601 year, week, and day
     as a structured array.
@@ -592,7 +593,7 @@ def build_isocalendar_sarray(const int64_t[:] dtindex):
             if dtindex[i] == NPY_NAT:
                 ret_val = 0, 0, 0
             else:
-                dt64_to_dtstruct(dtindex[i], &dts)
+                pandas_datetime_to_datetimestruct(dtindex[i], reso, &dts)
                 ret_val = get_iso_calendar(dts.year, dts.month, dts.day)
 
             iso_years[i] = ret_val[0]

pandas/core/arrays/datetimes.py

@@ -136,7 +136,7 @@ def f(self):
                     values, field, self.freqstr, month_kw, reso=self._reso
                 )
             else:
-                result = fields.get_date_field(values, field)
+                result = fields.get_date_field(values, field, reso=self._reso)
 
             # these return a boolean by-definition
             return result
@@ -146,7 +146,7 @@ def f(self):
             result = self._maybe_mask_results(result, fill_value=None)
 
         else:
-            result = fields.get_date_field(values, field)
+            result = fields.get_date_field(values, field, reso=self._reso)
             result = self._maybe_mask_results(
                 result, fill_value=None, convert="float64"
             )
@@ -1403,7 +1403,7 @@ def isocalendar(self) -> DataFrame:
         from pandas import DataFrame
 
         values = self._local_timestamps()
-        sarray = fields.build_isocalendar_sarray(values)
+        sarray = fields.build_isocalendar_sarray(values, reso=self._reso)
         iso_calendar_df = DataFrame(
             sarray, columns=["year", "week", "day"], dtype="UInt32"
         )

pandas/tests/arrays/test_datetimes.py

@@ -12,7 +12,15 @@
 
 
 class TestNonNano:
-    @pytest.mark.parametrize("unit,reso", [("s", 7), ("ms", 8), ("us", 9)])
+    @pytest.fixture(params=["s", "ms", "us"])
+    def unit(self, request):
+        return request.param
+
+    @pytest.fixture
+    def reso(self, unit):
+        # TODO: avoid hard-coding
+        return {"s": 7, "ms": 8, "us": 9}[unit]
+
     @pytest.mark.xfail(reason="_box_func is not yet patched to get reso right")
     def test_non_nano(self, unit, reso):
         arr = np.arange(5, dtype=np.int64).view(f"M8[{unit}]")
@@ -21,6 +29,22 @@ def test_non_nano(self, unit, reso):
         assert dta.dtype == arr.dtype
         assert dta[0]._reso == reso
 
+    @pytest.mark.filterwarnings(
+        "ignore:weekofyear and week have been deprecated:FutureWarning"
+    )
+    @pytest.mark.parametrize(
+        "field", DatetimeArray._field_ops + DatetimeArray._bool_ops
+    )
+    def test_fields(self, unit, reso, field):
+        dti = pd.date_range("2016-01-01", periods=55, freq="D")
+        arr = np.asarray(dti).astype(f"M8[{unit}]")
+
+        dta = DatetimeArray._simple_new(arr, dtype=arr.dtype)
+
+        res = getattr(dta, field)
+        expected = getattr(dti._data, field)
+        tm.assert_numpy_array_equal(res, expected)
+
 
 class TestDatetimeArrayComparisons:
     # TODO: merge this into tests/arithmetic/test_datetime64 once it is