DEPR: remove deprecated freqs/abbrevs 'A', 'A-DEC', 'A-JAN', etc.

pandas/_libs/tslibs/dtypes.pyx

@@ -273,19 +273,6 @@ cdef dict c_OFFSET_DEPR_FREQSTR = {
     "Y-SEP": "YE-SEP",
     "Y-OCT": "YE-OCT",
     "Y-NOV": "YE-NOV",
-    "A": "YE",
-    "A-DEC": "YE-DEC",
-    "A-JAN": "YE-JAN",
-    "A-FEB": "YE-FEB",
-    "A-MAR": "YE-MAR",
-    "A-APR": "YE-APR",
-    "A-MAY": "YE-MAY",
-    "A-JUN": "YE-JUN",
-    "A-JUL": "YE-JUL",
-    "A-AUG": "YE-AUG",
-    "A-SEP": "YE-SEP",
-    "A-OCT": "YE-OCT",
-    "A-NOV": "YE-NOV",
     "BY": "BYE",
     "BY-DEC": "BYE-DEC",
     "BY-JAN": "BYE-JAN",
@@ -336,20 +323,6 @@ cdef dict c_REVERSE_OFFSET_DEPR_FREQSTR = {
 
 # Map deprecated resolution abbreviations to correct resolution abbreviations
 cdef dict c_DEPR_ABBREVS = {
-    "A": "Y",
-    "a": "Y",
-    "A-DEC": "Y-DEC",
-    "A-JAN": "Y-JAN",
-    "A-FEB": "Y-FEB",
-    "A-MAR": "Y-MAR",
-    "A-APR": "Y-APR",
-    "A-MAY": "Y-MAY",
-    "A-JUN": "Y-JUN",
-    "A-JUL": "Y-JUL",
-    "A-AUG": "Y-AUG",
-    "A-SEP": "Y-SEP",
-    "A-OCT": "Y-OCT",
-    "A-NOV": "Y-NOV",
     "BA": "BY",
     "BA-DEC": "BY-DEC",
     "BA-JAN": "BY-JAN",

pandas/_libs/tslibs/offsets.pyx

@@ -4885,14 +4885,6 @@ cpdef to_offset(freq, bint is_period=False):
                             f"instead of \'{name}\'"
                         )
                 elif is_period and name.upper() in c_OFFSET_DEPR_FREQSTR:
-                    if name.upper().startswith("A"):
-                        warnings.warn(
-                            f"\'{name}\' is deprecated and will be removed in a future "
-                            f"version, please use "
-                            f"\'{c_DEPR_ABBREVS.get(name.upper())}\' instead.",
-                            FutureWarning,
-                            stacklevel=find_stack_level(),
-                        )
                     if name.upper() != name:
                         warnings.warn(
                             f"\'{name}\' is deprecated and will be removed in "

pandas/tests/arrays/test_datetimes.py

@@ -772,11 +772,8 @@ def test_iter_zoneinfo_fold(self, tz):
             ("2QE-SEP", "2Q-SEP"),
             ("1YE", "1Y"),
             ("2YE-MAR", "2Y-MAR"),
-            ("1YE", "1A"),
-            ("2YE-MAR", "2A-MAR"),
             ("2ME", "2m"),
             ("2QE-SEP", "2q-sep"),
-            ("2YE-MAR", "2a-mar"),
             ("2YE", "2y"),
         ],
     )
@@ -826,6 +823,13 @@ def test_date_range_lowercase_frequency_deprecated(self, freq_depr):
             result = pd.date_range("1/1/2000", periods=4, freq=freq_depr)
         tm.assert_index_equal(result, expected)
 
+    @pytest.mark.parametrize("freq", ["1A", "2A-MAR", "2a-mar"])
+    def test_date_range_frequency_A_raises(self, freq):
+        msg = f"Invalid frequency: {freq}"
+
+        with pytest.raises(ValueError, match=msg):
+            pd.date_range("1/1/2000", periods=4, freq=freq)
+
 
 def test_factorize_sort_without_freq():
     dta = DatetimeArray._from_sequence([0, 2, 1], dtype="M8[ns]")

pandas/tests/frame/methods/test_asfreq.py

@@ -242,8 +242,6 @@ def test_asfreq_2ME(self, freq, freq_half):
             ("2BQE-SEP", "2BQ-SEP"),
             ("1YE", "1Y"),
             ("2YE-MAR", "2Y-MAR"),
-            ("1YE", "1A"),
-            ("2YE-MAR", "2A-MAR"),
             ("2BYE-MAR", "2BA-MAR"),
         ],
     )
@@ -283,3 +281,19 @@ def test_asfreq_unsupported_freq(self, freq, error_msg):
 
         with pytest.raises(ValueError, match=error_msg):
             df.asfreq(freq=freq)
+
+    @pytest.mark.parametrize(
+        "freq, freq_depr",
+        [
+            ("1YE", "1A"),
+            ("2YE-MAR", "2A-MAR"),
+        ],
+    )
+    def test_asfreq_frequency_A_raisees(self, freq, freq_depr):
+        msg = f"Invalid frequency: {freq_depr[1:]}"
+
+        index = date_range("1/1/2000", periods=4, freq=f"{freq[1:]}")
+        df = DataFrame({"s": Series([0.0, 1.0, 2.0, 3.0], index=index)})
+
+        with pytest.raises(ValueError, match=msg):
+            df.asfreq(freq=freq_depr)

pandas/tests/indexes/datetimes/methods/test_to_period.py

@@ -97,11 +97,9 @@ def test_dti_to_period_2monthish(self, freq_offset, freq_period):
             ("2QE-SEP", "2Q-SEP"),
             ("1YE", "1Y"),
             ("2YE-MAR", "2Y-MAR"),
-            ("1YE", "1A"),
-            ("2YE-MAR", "2A-MAR"),
         ],
     )
-    def test_to_period_frequency_M_Q_Y_A_deprecated(self, freq, freq_depr):
+    def test_to_period_frequency_M_Q_Y_deprecated(self, freq, freq_depr):
         # GH#9586
         msg = f"'{freq_depr[1:]}' is deprecated and will be removed "
         f"in a future version, please use '{freq[1:]}' instead."

pandas/tests/indexes/datetimes/test_date_range.py

@@ -800,13 +800,11 @@ def test_frequencies_H_T_S_L_U_N_deprecated(self, freq, freq_depr):
     @pytest.mark.parametrize(
         "freq,freq_depr",
         [
-            ("200YE", "200A"),
             ("YE", "Y"),
-            ("2YE-MAY", "2A-MAY"),
             ("YE-MAY", "Y-MAY"),
         ],
     )
-    def test_frequencies_A_deprecated_Y_renamed(self, freq, freq_depr):
+    def test_frequencies_Y_renamed(self, freq, freq_depr):
         # GH#9586, GH#54275
         freq_msg = re.split("[0-9]*", freq, maxsplit=1)[1]
         freq_depr_msg = re.split("[0-9]*", freq_depr, maxsplit=1)[1]
@@ -836,6 +834,14 @@ def test_date_range_bday(self):
         assert idx[0] == sdate + 0 * offsets.BDay()
         assert idx.freq == "B"
 
+    @pytest.mark.parametrize("freq", ["200A", "2A-MAY"])
+    def test_frequency_A_raises(self, freq):
+        freq_msg = re.split("[0-9]*", freq, maxsplit=1)[1]
+        msg = f"Invalid frequency: {freq_msg}"
+
+        with pytest.raises(ValueError, match=msg):
+            date_range("1/1/2000", periods=2, freq=freq)
+
 
 class TestDateRangeTZ:
     """Tests for date_range with timezones"""

pandas/tests/indexes/period/test_period_range.py

@@ -205,23 +205,6 @@ def test_constructor_U(self):
         with pytest.raises(ValueError, match="Invalid frequency: X"):
             period_range("2007-1-1", periods=500, freq="X")
 
-    @pytest.mark.parametrize(
-        "freq,freq_depr",
-        [
-            ("2Y", "2A"),
-            ("2Y", "2a"),
-            ("2Y-AUG", "2A-AUG"),
-            ("2Y-AUG", "2A-aug"),
-        ],
-    )
-    def test_a_deprecated_from_time_series(self, freq, freq_depr):
-        # GH#52536
-        msg = f"'{freq_depr[1:]}' is deprecated and will be removed in a "
-        f"future version. Please use '{freq[1:]}' instead."
-
-        with tm.assert_produces_warning(FutureWarning, match=msg):
-            period_range(freq=freq_depr, start="1/1/2001", end="12/1/2009")
-
     @pytest.mark.parametrize("freq_depr", ["2H", "2MIN", "2S", "2US", "2NS"])
     def test_uppercase_freq_deprecated_from_time_series(self, freq_depr):
         # GH#52536, GH#54939
@@ -239,3 +222,10 @@ def test_lowercase_freq_deprecated_from_time_series(self, freq_depr):
 
         with tm.assert_produces_warning(FutureWarning, match=msg):
             period_range(freq=freq_depr, start="1/1/2001", end="12/1/2009")
+
+    @pytest.mark.parametrize("freq", ["2A", "2a", "2A-AUG", "2A-aug"])
+    def test_A_raises_from_time_series(self, freq):
+        msg = f"Invalid frequency: {freq}"
+
+        with pytest.raises(ValueError, match=msg):
+            period_range(freq=freq, start="1/1/2001", end="12/1/2009")

pandas/tests/resample/test_datetime_index.py

@@ -2047,11 +2047,9 @@ def test_resample_empty_series_with_tz():
         ("2QE-SEP", "2Q-SEP"),
         ("1YE", "1Y"),
         ("2YE-MAR", "2Y-MAR"),
-        ("1YE", "1A"),
-        ("2YE-MAR", "2A-MAR"),
     ],
 )
-def test_resample_M_Q_Y_A_deprecated(freq, freq_depr):
+def test_resample_M_Q_Y_deprecated(freq, freq_depr):
     # GH#9586
     depr_msg = f"'{freq_depr[1:]}' is deprecated and will be removed "
     f"in a future version, please use '{freq[1:]}' instead."
@@ -2174,3 +2172,12 @@ def test_arrow_timestamp_resample(tz):
     expected = Series(np.arange(5, dtype=np.float64), index=idx)
     result = expected.resample("1D").mean()
     tm.assert_series_equal(result, expected)
+
+
+@pytest.mark.parametrize("freq", ["1A", "2A-MAR"])
+def test_resample_A_raises(freq):
+    msg = f"Invalid frequency: {freq[1:]}"
+
+    s = Series(range(10), index=date_range("20130101", freq="d", periods=10))
+    with pytest.raises(ValueError, match=msg):
+        s.resample(freq).mean()

pandas/tests/tslibs/test_resolution.py

@@ -48,8 +48,8 @@ def test_get_attrname_from_abbrev(freqstr, expected):
     assert reso.attrname == expected
 
 
-@pytest.mark.parametrize("freq", ["A", "H", "T", "S", "L", "U", "N"])
-def test_units_A_H_T_S_L_U_N_deprecated_from_attrname_to_abbrevs(freq):
+@pytest.mark.parametrize("freq", ["H", "T", "S", "L", "U", "N"])
+def test_units_H_T_S_L_U_N_deprecated_from_attrname_to_abbrevs(freq):
     # GH#52536
     msg = f"'{freq}' is deprecated and will be removed in a future version."