Add month names

Fix localiztion of months

Add series test and whatsnew notes

Modify test and lint

Add Timestamp rst

Address comments

Lint, move whatsnew, remove hardcoded Monday, check that get_locale is None

doc/source/api.rst

@@ -497,6 +497,7 @@ These can be accessed like ``Series.dt.<property>``.
    Series.dt.time
    Series.dt.year
    Series.dt.month
+   Series.dt.month_name
    Series.dt.day
    Series.dt.hour
    Series.dt.minute
@@ -1537,6 +1538,7 @@ Time/Date Components
 
    DatetimeIndex.year
    DatetimeIndex.month
+   DatetimeIndex.month_name
    DatetimeIndex.day
    DatetimeIndex.hour
    DatetimeIndex.minute
@@ -1757,6 +1759,7 @@ Properties
     Timestamp.microsecond
     Timestamp.min
     Timestamp.month
+    Timestamp.month_name
     Timestamp.nanosecond
     Timestamp.quarter
     Timestamp.resolution

doc/source/whatsnew/v0.22.0.txt

@@ -24,6 +24,7 @@ Other Enhancements
 
 - Better support for :func:`Dataframe.style.to_excel` output with the ``xlsxwriter`` engine. (:issue:`16149`)
 - :func:`pandas.tseries.frequencies.to_offset` now accepts leading '+' signs e.g. '+1h'. (:issue:`18171`)
+- :attr:`Timestamp.month_name`, :attr:`DatetimeIndex.month_name`, and :attr:`Series.dt.month_name` are now available (:issue:`12805`)
 -
 
 .. _whatsnew_0220.api_breaking:
@@ -91,7 +92,7 @@ Bug Fixes
 Conversion
 ^^^^^^^^^^
 
--
+- Bug in :attr:`Timestamp.weekday_name` and :attr:`DatetimeIndex.weekday_name` not returning locale aware values (:issue:`12806`)
 -
 -
 

pandas/_libs/tslib.pyx

@@ -68,6 +68,7 @@ from khash cimport (
     kh_resize_int64, kh_get_int64)
 
 from .tslibs.parsing import parse_datetime_string
+from .tslibs.strptime import LocaleTime
 
 cimport cython
 
@@ -533,10 +534,15 @@ class Timestamp(_Timestamp):
 
     @property
     def weekday_name(self):
-        cdef dict wdays = {0: 'Monday', 1: 'Tuesday', 2: 'Wednesday',
-                           3: 'Thursday', 4: 'Friday', 5: 'Saturday',
-                           6: 'Sunday'}
-        return wdays[self.weekday()]
+        cdef object locale_time = LocaleTime()
+        cdef dict wdays = dict(enumerate(locale_time.f_weekday))
+        return wdays[self.weekday()].capitalize()
+
+    @property
+    def month_name(self):
+        cdef object locale_time = LocaleTime()
+        cdef dict months = dict(enumerate(locale_time.f_month))
+        return months[self.month].capitalize()
 
     @property
     def dayofyear(self):

pandas/_libs/tslibs/fields.pyx

@@ -28,6 +28,8 @@ cimport util
 
 cdef int64_t NPY_NAT = util.get_nat()
 
+from pandas._libs.tslibs.strptime import LocaleTime
+
 
 def build_field_sarray(ndarray[int64_t] dtindex):
     """
@@ -83,24 +85,31 @@ def get_date_name_field(ndarray[int64_t] dtindex, object field):
         ndarray[object] out
         pandas_datetimestruct dts
         int dow
-
-    _dayname = np.array(
-        ['Monday', 'Tuesday', 'Wednesday', 'Thursday',
-            'Friday', 'Saturday', 'Sunday'],
-        dtype=np.object_)
+        object locale_time = LocaleTime()
 
     count = len(dtindex)
     out = np.empty(count, dtype=object)
 
     if field == 'weekday_name':
+        _dayname = np.array(locale_time.f_weekday, dtype=np.object_)
         for i in range(count):
             if dtindex[i] == NPY_NAT:
                 out[i] = np.nan
                 continue
 
             dt64_to_dtstruct(dtindex[i], &dts)
             dow = dayofweek(dts.year, dts.month, dts.day)
-            out[i] = _dayname[dow]
+            out[i] = _dayname[dow].capitalize()
+        return out
+    elif field == 'month_name':
+        _monthname = np.array(locale_time.f_month, dtype=np.object_)
+        for i in range(count):
+            if dtindex[i] == NPY_NAT:
+                out[i] = np.nan
+                continue
+
+            dt64_to_dtstruct(dtindex[i], &dts)
+            out[i] = _monthname[dts.month].capitalize()
         return out
 
     raise ValueError("Field %s not supported" % field)

pandas/_libs/tslibs/nattype.pyx

@@ -301,6 +301,7 @@ class NaTType(_NaT):
     daysinmonth = property(fget=lambda self: np.nan)
     dayofweek = property(fget=lambda self: np.nan)
     weekday_name = property(fget=lambda self: np.nan)
+    month_name = property(fget=lambda self: np.nan)
 
     # inject Timedelta properties
     days = property(fget=lambda self: np.nan)

pandas/core/indexes/datetimes.py

@@ -248,7 +248,7 @@ def _join_i8_wrapper(joinf, **kwargs):
     _bool_ops = ['is_month_start', 'is_month_end',
                  'is_quarter_start', 'is_quarter_end', 'is_year_start',
                  'is_year_end', 'is_leap_year']
-    _object_ops = ['weekday_name', 'freq', 'tz']
+    _object_ops = ['weekday_name', 'month_name', 'freq', 'tz']
     _field_ops = ['year', 'month', 'day', 'hour', 'minute', 'second',
                   'weekofyear', 'week', 'weekday', 'dayofweek',
                   'dayofyear', 'quarter', 'days_in_month',
@@ -1581,6 +1581,11 @@ def _set_freq(self, value):
         'weekday_name',
         "The name of day in a week (ex: Friday)\n\n.. versionadded:: 0.18.1")
 
+    month_name = _field_accessor(
+        'month_name',
+        'month_name',
+        "The name of month in a year (ex: May)\n\n.. versionadded:: 0.21.1")
+
     dayofyear = _field_accessor('dayofyear', 'doy',
                                 "The ordinal day of the year")
     quarter = _field_accessor('quarter', 'q', "The quarter of the date")

pandas/tests/indexes/datetimes/test_misc.py

@@ -1,3 +1,6 @@
+import locale
+import calendar
+
 import pytest
 
 import numpy as np
@@ -173,7 +176,6 @@ def test_normalize(self):
 class TestDatetime64(object):
 
     def test_datetimeindex_accessors(self):
-
         dti_naive = DatetimeIndex(freq='D', start=datetime(1998, 1, 1),
                                   periods=365)
         # GH 13303
@@ -220,23 +222,6 @@ def test_datetimeindex_accessors(self):
             assert not dti.is_year_end[0]
             assert dti.is_year_end[364]
 
-            # GH 11128
-            assert dti.weekday_name[4] == u'Monday'
-            assert dti.weekday_name[5] == u'Tuesday'
-            assert dti.weekday_name[6] == u'Wednesday'
-            assert dti.weekday_name[7] == u'Thursday'
-            assert dti.weekday_name[8] == u'Friday'
-            assert dti.weekday_name[9] == u'Saturday'
-            assert dti.weekday_name[10] == u'Sunday'
-
-            assert Timestamp('2016-04-04').weekday_name == u'Monday'
-            assert Timestamp('2016-04-05').weekday_name == u'Tuesday'
-            assert Timestamp('2016-04-06').weekday_name == u'Wednesday'
-            assert Timestamp('2016-04-07').weekday_name == u'Thursday'
-            assert Timestamp('2016-04-08').weekday_name == u'Friday'
-            assert Timestamp('2016-04-09').weekday_name == u'Saturday'
-            assert Timestamp('2016-04-10').weekday_name == u'Sunday'
-
             assert len(dti.year) == 365
             assert len(dti.month) == 365
             assert len(dti.day) == 365
@@ -342,6 +327,31 @@ def test_datetimeindex_accessors(self):
         assert dates.weekofyear.tolist() == expected
         assert [d.weekofyear for d in dates] == expected
 
+    # GH 12806
+    @pytest.mark.skipif(tm.get_locales() is None or len(tm.get_locales()) == 0,
+                        reason='No available locales')
+    @pytest.mark.parametrize('time_locale', tm.get_locales())
+    def test_datetime_name_accessors(self, time_locale):
+        with tm.set_locale(time_locale, locale.LC_TIME):
+            # GH 11128
+            dti = DatetimeIndex(freq='D', start=datetime(1998, 1, 1),
+                                periods=365)
+            for day, name in zip(range(4, 11), calendar.day_name):
+                # Test Monday -> Sunday
+                assert dti.weekday_name[day] == name.capitalize()
+                date = datetime(2016, 4, day)
+                assert Timestamp(date).weekday_name == name.capitalize()
+
+            # GH 12805
+            dti = DatetimeIndex(freq='M', start='2012', end='2013')
+            # Test January -> December
+            result = dti.month_name
+            expected = Index([month.capitalize()
+                              for month in calendar.month_name[1:]])
+            tm.assert_index_equal(result, expected)
+            for date, result in zip(dti, calendar.month_name[1:]):
+                assert date.month_name == result.capitalize()
+
     def test_nanosecond_field(self):
         dti = DatetimeIndex(np.arange(10))
 

pandas/tests/scalar/test_timestamp.py

@@ -1,6 +1,7 @@
 """ test the scalar Timestamp """
 
 import sys
+import locale
 import pytz
 import pytest
 import dateutil
@@ -597,13 +598,17 @@ def check(value, equal):
         for end in ends:
             assert getattr(ts, end)
 
-    @pytest.mark.parametrize('data, expected',
-                             [(Timestamp('2017-08-28 23:00:00'), 'Monday'),
-                              (Timestamp('2017-08-28 23:00:00', tz='EST'),
-                               'Monday')])
-    def test_weekday_name(self, data, expected):
+    # GH 12806
+    @pytest.mark.skipif(tm.get_locales() is None or len(tm.get_locales()) == 0,
+                        reason='No available locales')
+    @pytest.mark.parametrize('data',
+                             [Timestamp('2017-08-28 23:00:00'),
+                              Timestamp('2017-08-28 23:00:00', tz='EST')])
+    @pytest.mark.parametrize('time_locale', tm.get_locales())
+    def test_weekday_name(self, data, time_locale):
         # GH 17354
-        assert data.weekday_name == expected
+        with tm.set_locale(time_locale, locale.LC_TIME):
+            assert data.weekday_name == calendar.day_name[0].capitalize()
 
     def test_pprint(self):
         # GH12622

pandas/tests/series/test_datetime_values.py

@@ -32,7 +32,7 @@ def test_dt_namespace_accessor(self):
         ok_for_dt = DatetimeIndex._datetimelike_ops
         ok_for_dt_methods = ['to_period', 'to_pydatetime', 'tz_localize',
                              'tz_convert', 'normalize', 'strftime', 'round',
-                             'floor', 'ceil', 'weekday_name']
+                             'floor', 'ceil', 'weekday_name', 'month_name']
         ok_for_td = TimedeltaIndex._datetimelike_ops
         ok_for_td_methods = ['components', 'to_pytimedelta', 'total_seconds',
                              'round', 'floor', 'ceil']