CLN: Deprecate dayofweek/hello day_of_week (pandas-dev#9606)

Rename dayofweek properties in Period, Datetime, and PeriodArray classes.
Add day_of_week property to respective tests for each class.

Author: abhishekmangla

pandas/_libs/tslibs/nattype.pyx

@@ -361,7 +361,8 @@ class NaTType(_NaT):
     days_in_month = property(fget=lambda self: np.nan)
     daysinmonth = property(fget=lambda self: np.nan)
     dayofweek = property(fget=lambda self: np.nan)
-
+    day_of_week = property(fget=lambda self: np.nan)
+    
     # inject Timedelta properties
     days = property(fget=lambda self: np.nan)
     seconds = property(fget=lambda self: np.nan)

pandas/_libs/tslibs/period.pyx

@@ -1373,7 +1373,7 @@ cdef accessor _get_accessor_func(str field):
         return <accessor>pweek
     elif field == "day_of_year":
         return <accessor>pday_of_year
-    elif field == "weekday":
+    elif field == "weekday" or field == "day_of_week":
         return <accessor>pweekday
     elif field == "days_in_month":
         return <accessor>pdays_in_month
@@ -1882,7 +1882,7 @@ cdef class _Period(PeriodMixin):
         return self.weekofyear
 
     @property
-    def dayofweek(self) -> int:
+    def day_of_week(self) -> int:
         """
         Day of the week the period lies in, with Monday=0 and Sunday=6.
 
@@ -1900,38 +1900,43 @@ cdef class _Period(PeriodMixin):
 
         See Also
         --------
-        Period.dayofweek : Day of the week the period lies in.
-        Period.weekday : Alias of Period.dayofweek.
+        Period.day_of_week : Day of the week the period lies in.
+        Period.weekday : Alias of Period.day_of_week.
         Period.day : Day of the month.
         Period.dayofyear : Day of the year.
 
         Examples
         --------
         >>> per = pd.Period('2017-12-31 22:00', 'H')
-        >>> per.dayofweek
+        >>> per.day_of_week
         6
 
         For periods that span over multiple days, the day at the beginning of
         the period is returned.
 
         >>> per = pd.Period('2017-12-31 22:00', '4H')
-        >>> per.dayofweek
+        >>> per.day_of_week
         6
-        >>> per.start_time.dayofweek
+        >>> per.start_time.day_of_week
         6
 
         For periods with a frequency higher than days, the last day of the
         period is returned.
 
         >>> per = pd.Period('2018-01', 'M')
-        >>> per.dayofweek
+        >>> per.day_of_week
         2
-        >>> per.end_time.dayofweek
+        >>> per.end_time.day_of_week
         2
         """
         base = self._dtype._dtype_code
         return pweekday(self.ordinal, base)
 
+    @property
+    def dayofweek(self) -> int:
+        """This property is deprecated. Please use day_of_week instead."""
+        return self.day_of_week
+
     @property
     def weekday(self) -> int:
         """

pandas/_libs/tslibs/timestamps.pyx

@@ -538,12 +538,19 @@ cdef class _Timestamp(ABCTimestamp):
         return bool(ccalendar.is_leapyear(self.year))
 
     @property
-    def dayofweek(self) -> int:
+    def day_of_week(self) -> int:
         """
         Return day of the week.
         """
         return self.weekday()
 
+    @property
+    def dayofweek(self) -> int:
+        """
+        Deprecated. Use day_of_week instead.
+        """
+        return self.day_of_week
+
     @property
     def dayofyear(self) -> int:
         """

pandas/core/arrays/datetimes.py

@@ -177,6 +177,7 @@ class DatetimeArray(dtl.TimelikeOps, dtl.DatelikeOps):
         "week",
         "weekday",
         "dayofweek",
+        "day_of_week",
         "dayofyear",
         "quarter",
         "days_in_month",
@@ -1533,8 +1534,9 @@ def weekofyear(self):
     2017-01-08    6
     Freq: D, dtype: int64
     """
-    dayofweek = _field_accessor("dayofweek", "dow", _dayofweek_doc)
-    weekday = dayofweek
+    day_of_week = _field_accessor("day_of_week", "dow", _dayofweek_doc)
+    dayofweek = day_of_week
+    weekday = day_of_week
 
     dayofyear = _field_accessor(
         "dayofyear",

pandas/core/arrays/period.py

@@ -140,6 +140,7 @@ class PeriodArray(PeriodMixin, dtl.DatelikeOps):
         "weekday",
         "week",
         "dayofweek",
+        "day_of_week",
         "dayofyear",
         "quarter",
         "qyear",
@@ -381,12 +382,13 @@ def __arrow_array__(self, type=None):
         """,
     )
     week = weekofyear
-    dayofweek = _field_accessor(
-        "weekday",
+    day_of_week = _field_accessor(
+        "day_of_week",
         """
         The day of the week with Monday=0, Sunday=6.
         """,
     )
+    dayofweek = day_of_week
     weekday = dayofweek
     dayofyear = day_of_year = _field_accessor(
         "day_of_year",

pandas/core/indexes/datetimes.py

@@ -161,6 +161,7 @@ class DatetimeIndex(DatetimeTimedeltaMixin):
     weekofyear
     week
     dayofweek
+    day_of_week
     weekday
     quarter
     tz

pandas/core/indexes/period.py

@@ -95,6 +95,7 @@ class PeriodIndex(DatetimeIndexOpsMixin, Int64Index):
     ----------
     day
     dayofweek
+    day_of_week
     dayofyear
     days_in_month
     daysinmonth

pandas/tests/generic/test_finalize.py

@@ -678,6 +678,8 @@ def test_datetime_method(method):
         "microsecond",
         "nanosecond",
         "dayofweek",
+        # Add better named field for GH-9606
+        "day_of_week",
         "dayofyear",
         "quarter",
         "is_month_start",

pandas/tests/indexes/datetimes/test_scalar_compat.py

@@ -38,6 +38,8 @@ def test_dti_date_out_of_range(self, data):
         "field",
         [
             "dayofweek",
+            # Add better named field for GH-9606
+            "day_of_week",
             "dayofyear",
             "quarter",
             "days_in_month",

pandas/tests/indexes/period/test_period.py

@@ -249,6 +249,8 @@ def _check_all_fields(self, periodindex):
             "weekofyear",
             "week",
             "dayofweek",
+            # Add better named field for GH-9606
+            "day_of_week",
             "dayofyear",
             "quarter",
             "qyear",

pandas/tests/scalar/timestamp/test_timestamp.py

@@ -26,6 +26,7 @@ def test_properties_business(self):
         ts = Timestamp("2017-10-01", freq="B")
         control = Timestamp("2017-10-01")
         assert ts.dayofweek == 6
+        assert ts.day_of_week == 6
         assert not ts.is_month_start  # not a weekday
         assert not ts.is_quarter_start  # not a weekday
         # Control case: non-business is month/qtr start
@@ -35,6 +36,7 @@ def test_properties_business(self):
         ts = Timestamp("2017-09-30", freq="B")
         control = Timestamp("2017-09-30")
         assert ts.dayofweek == 5
+        assert ts.day_of_week == 5
         assert not ts.is_month_end  # not a weekday
         assert not ts.is_quarter_end  # not a weekday
         # Control case: non-business is month/qtr start
@@ -61,6 +63,7 @@ def check(value, equal):
         check(ts.microsecond, 100)
         check(ts.nanosecond, 1)
         check(ts.dayofweek, 6)
+        check(ts.day_of_week, 6)
         check(ts.quarter, 2)
         check(ts.dayofyear, 130)
         check(ts.week, 19)
@@ -81,6 +84,7 @@ def check(value, equal):
         check(ts.microsecond, 0)
         check(ts.nanosecond, 0)
         check(ts.dayofweek, 2)
+        check(ts.day_of_week, 2)
         check(ts.quarter, 4)
         check(ts.dayofyear, 365)
         check(ts.week, 1)