DEPR: Deprecate legacy offsets

doc/source/timeseries.rst

@@ -656,7 +656,7 @@ apply the offset to each element.
    rng + DateOffset(months=2)
    s + DateOffset(months=2)
    s - DateOffset(months=2)
-   
+
 If the offset class maps directly to a ``Timedelta`` (``Day``, ``Hour``,
 ``Minute``, ``Second``, ``Micro``, ``Milli``, ``Nano``) it can be
 used exactly like a ``Timedelta`` - see the
@@ -670,7 +670,7 @@ used exactly like a ``Timedelta`` - see the
    td + Minute(15)
 
 Note that some offsets (such as ``BQuarterEnd``) do not have a
-vectorized implementation.  They can still be used but may 
+vectorized implementation.  They can still be used but may
 calculate signficantly slower and will raise a ``PerformanceWarning``
 
 .. ipython:: python
@@ -882,10 +882,10 @@ frequencies. We will refer to these aliases as *offset aliases*
     "BAS", "business year start frequency"
     "BH", "business hour frequency"
     "H", "hourly frequency"
-    "T", "minutely frequency"
+    "T, min", "minutely frequency"
     "S", "secondly frequency"
-    "L", "milliseonds"
-    "U", "microseconds"
+    "L, ms", "milliseonds"
+    "U, us", "microseconds"
     "N", "nanoseconds"
 
 Combining Aliases
@@ -953,11 +953,12 @@ These can be used as arguments to ``date_range``, ``bdate_range``, constructors
 for ``DatetimeIndex``, as well as various other timeseries-related functions
 in pandas.
 
+.. _timeseries.legacyaliases:
+
 Legacy Aliases
 ~~~~~~~~~~~~~~
-Note that prior to v0.8.0, time rules had a slightly different look. pandas
-will continue to support the legacy time rules for the time being but it is
-strongly recommended that you switch to using the new offset aliases.
+Note that prior to v0.8.0, time rules had a slightly different look. These are
+deprecated in v0.17.0, and removed in future version.
 
 .. csv-table::
     :header: "Legacy Time Rule", "Offset Alias"
@@ -987,9 +988,7 @@ strongly recommended that you switch to using the new offset aliases.
     "A\@OCT", "BA\-OCT"
     "A\@NOV", "BA\-NOV"
     "A\@DEC", "BA\-DEC"
-    "min", "T"
-    "ms", "L"
-    "us", "U"
+
 
 As you can see, legacy quarterly and annual frequencies are business quarters
 and business year ends. Please also note the legacy time rule for milliseconds

doc/source/whatsnew/v0.17.0.txt

@@ -653,6 +653,7 @@ Deprecations
   ``DataFrame.add(other, fill_value=0)`` and ``DataFrame.mul(other, fill_value=1.)``
   (:issue:`10735`).
 - ``TimeSeries`` deprecated in favor of ``Series`` (note that this has been alias since 0.13.0), (:issue:`10890`)
+- Legacy offsets (like ``'A@JAN'``) listed in :ref:`here <timeseries.legacyaliases>` are deprecated (note that this has been alias since 0.8.0), (:issue:`10878`)
 - ``WidePanel`` deprecated in favor of ``Panel``, ``LongPanel`` in favor of ``DataFrame`` (note these have been aliases since < 0.11.0), (:issue:`10892`)
 
 .. _whatsnew_0170.prior_deprecations:

pandas/tseries/frequencies.py

@@ -2,6 +2,7 @@
 from pandas.compat import range, long, zip
 from pandas import compat
 import re
+import warnings
 
 import numpy as np
 
@@ -335,29 +336,18 @@ def get_period_alias(offset_str):
 _rule_aliases = {
     # Legacy rules that will continue to map to their original values
     # essentially for the rest of time
-
     'WEEKDAY': 'B',
     'EOM': 'BM',
-
     'W@MON': 'W-MON',
     'W@TUE': 'W-TUE',
     'W@WED': 'W-WED',
     'W@THU': 'W-THU',
     'W@FRI': 'W-FRI',
     'W@SAT': 'W-SAT',
     'W@SUN': 'W-SUN',
-    'W': 'W-SUN',
-
     'Q@JAN': 'BQ-JAN',
     'Q@FEB': 'BQ-FEB',
     'Q@MAR': 'BQ-MAR',
-    'Q': 'Q-DEC',
-
-    'A': 'A-DEC',  # YearEnd(month=12),
-    'AS': 'AS-JAN',  # YearBegin(month=1),
-    'BA': 'BA-DEC',  # BYearEnd(month=12),
-    'BAS': 'BAS-JAN',  # BYearBegin(month=1),
-
     'A@JAN': 'BA-JAN',
     'A@FEB': 'BA-FEB',
     'A@MAR': 'BA-MAR',
@@ -370,8 +360,17 @@ def get_period_alias(offset_str):
     'A@OCT': 'BA-OCT',
     'A@NOV': 'BA-NOV',
     'A@DEC': 'BA-DEC',
+}
+
+_lite_rule_alias = {
+    'W': 'W-SUN',
+    'Q': 'Q-DEC',
+
+    'A': 'A-DEC',  # YearEnd(month=12),
+    'AS': 'AS-JAN',  # YearBegin(month=1),
+    'BA': 'BA-DEC',  # BYearEnd(month=12),
+    'BAS': 'BAS-JAN',  # BYearBegin(month=1),
 
-    # lite aliases
     'Min': 'T',
     'min': 'T',
     'ms': 'L',
@@ -386,6 +385,7 @@ def get_period_alias(offset_str):
 
 # Note that _rule_aliases is not 1:1 (d[BA]==d[A@DEC]), and so traversal
 # order matters when constructing an inverse. we pick one. #2331
+# Used in get_legacy_offset_name
 _legacy_reverse_map = dict((v, k) for k, v in
                            reversed(sorted(compat.iteritems(_rule_aliases))))
 
@@ -501,6 +501,9 @@ def get_base_alias(freqstr):
 _dont_uppercase = set(('MS', 'ms'))
 
 
+_LEGACY_FREQ_WARNING = 'Freq "{0}" is deprecated, use "{1}" as alternative.'
+
+
 def get_offset(name):
     """
     Return DateOffset object associated with rule name
@@ -513,12 +516,26 @@ def get_offset(name):
         name = name.upper()
 
         if name in _rule_aliases:
-            name = _rule_aliases[name]
+            new = _rule_aliases[name]
+            warnings.warn(_LEGACY_FREQ_WARNING.format(name, new),
+                          FutureWarning)
+            name = new
         elif name.lower() in _rule_aliases:
-            name = _rule_aliases[name.lower()]
+            new = _rule_aliases[name.lower()]
+            warnings.warn(_LEGACY_FREQ_WARNING.format(name, new),
+                          FutureWarning)
+            name = new
+
+        name = _lite_rule_alias.get(name, name)
+        name = _lite_rule_alias.get(name.lower(), name)
+
     else:
         if name in _rule_aliases:
-            name = _rule_aliases[name]
+            new = _rule_aliases[name]
+            warnings.warn(_LEGACY_FREQ_WARNING.format(name, new),
+                          FutureWarning)
+            name = new
+        name = _lite_rule_alias.get(name, name)
 
     if name not in _offset_map:
         try:
@@ -561,6 +578,9 @@ def get_legacy_offset_name(offset):
     """
     Return the pre pandas 0.8.0 name for the date offset
     """
+
+    # This only used in test_timeseries_legacy.py
+
     name = offset.name
     return _legacy_reverse_map.get(name, name)
 
@@ -754,10 +774,21 @@ def _period_alias_dictionary():
 
 def _period_str_to_code(freqstr):
     # hack
-    freqstr = _rule_aliases.get(freqstr, freqstr)
+    if freqstr in _rule_aliases:
+        new = _rule_aliases[freqstr]
+        warnings.warn(_LEGACY_FREQ_WARNING.format(freqstr, new),
+                      FutureWarning)
+        freqstr = new
+    freqstr = _lite_rule_alias.get(freqstr, freqstr)
 
     if freqstr not in _dont_uppercase:
-        freqstr = _rule_aliases.get(freqstr.lower(), freqstr)
+        lower = freqstr.lower()
+        if lower in _rule_aliases:
+            new = _rule_aliases[lower]
+            warnings.warn(_LEGACY_FREQ_WARNING.format(lower, new),
+                          FutureWarning)
+            freqstr = new
+        freqstr = _lite_rule_alias.get(lower, freqstr)
 
     try:
         if freqstr not in _dont_uppercase:
@@ -766,6 +797,8 @@ def _period_str_to_code(freqstr):
     except KeyError:
         try:
             alias = _period_alias_dict[freqstr]
+            warnings.warn(_LEGACY_FREQ_WARNING.format(freqstr, alias),
+                          FutureWarning)
         except KeyError:
             raise ValueError("Unknown freqstr: %s" % freqstr)
 

pandas/tseries/offsets.py

@@ -2650,14 +2650,13 @@ def generate_range(start=None, end=None, periods=None,
 
 prefix_mapping['N'] = Nano
 
-
 def _make_offset(key):
     """Gets offset based on key. KeyError if prefix is bad, ValueError if
     suffix is bad. All handled by `get_offset` in tseries/frequencies. Not
     public."""
     if key is None:
         return None
-    split = key.replace('@', '-').split('-')
+    split = key.split('-')
     klass = prefix_mapping[split[0]]
     # handles case where there's no suffix (and will TypeError if too many '-')
     obj = klass._from_name(*split[1:])

pandas/tseries/tests/test_frequencies.py

@@ -529,9 +529,13 @@ def test_series(self):
         self.assertRaises(ValueError, lambda : frequencies.infer_freq(Series(['foo','bar'])))
 
         # cannot infer on PeriodIndex
-        for freq in [None, 'L', 'Y']:
+        for freq in [None, 'L']:
             s = Series(period_range('2013',periods=10,freq=freq))
             self.assertRaises(TypeError, lambda : frequencies.infer_freq(s))
+        for freq in ['Y']:
+            with tm.assert_produces_warning(FutureWarning):
+                s = Series(period_range('2013',periods=10,freq=freq))
+            self.assertRaises(TypeError, lambda : frequencies.infer_freq(s))
 
         # DateTimeIndex
         for freq in ['M', 'L', 'S']:
@@ -543,6 +547,19 @@ def test_series(self):
         inferred = frequencies.infer_freq(s)
         self.assertEqual(inferred,'D')
 
+    def test_legacy_offset_warnings(self):
+        for k, v in compat.iteritems(frequencies._rule_aliases):
+            with tm.assert_produces_warning(FutureWarning):
+                result = frequencies.get_offset(k)
+            exp = frequencies.get_offset(v)
+            self.assertEqual(result, exp)
+
+            with tm.assert_produces_warning(FutureWarning):
+                idx = date_range('2011-01-01', periods=5, freq=k)
+            exp = date_range('2011-01-01', periods=5, freq=v)
+            self.assert_index_equal(idx, exp)
+
+
 MONTHS = ['JAN', 'FEB', 'MAR', 'APR', 'MAY', 'JUN', 'JUL', 'AUG', 'SEP',
           'OCT', 'NOV', 'DEC']
 

pandas/tseries/tests/test_offsets.py

@@ -3615,7 +3615,6 @@ def test_get_offset():
              ('Bm', BMonthEnd()), ('W-MON', Week(weekday=0)),
              ('W-TUE', Week(weekday=1)), ('W-WED', Week(weekday=2)),
              ('W-THU', Week(weekday=3)), ('W-FRI', Week(weekday=4)),
-             ('w@Sat', Week(weekday=5)),
              ("RE-N-DEC-MON", makeFY5253NearestEndMonth(weekday=0, startingMonth=12)),
              ("RE-L-DEC-TUE", makeFY5253LastOfMonth(weekday=1, startingMonth=12)),
              ("REQ-L-MAR-TUE-4", makeFY5253LastOfMonthQuarter(weekday=1, startingMonth=3, qtr_with_extra_week=4)),
@@ -3628,6 +3627,13 @@ def test_get_offset():
         assert offset == expected, ("Expected %r to yield %r (actual: %r)" %
                                     (name, expected, offset))
 
+def test_get_offset_legacy():
+    pairs = [('w@Sat', Week(weekday=5))]
+    for name, expected in pairs:
+        with tm.assert_produces_warning(FutureWarning):
+            offset = get_offset(name)
+        assert offset == expected, ("Expected %r to yield %r (actual: %r)" %
+                                    (name, expected, offset))
 
 class TestParseTimeString(tm.TestCase):
 
@@ -3663,11 +3669,18 @@ def test_get_standard_freq():
     assert fstr == get_standard_freq('w')
     assert fstr == get_standard_freq('1w')
     assert fstr == get_standard_freq(('W', 1))
-    assert fstr == get_standard_freq('WeEk')
+
+    with tm.assert_produces_warning(FutureWarning):
+        result = get_standard_freq('WeEk')
+    assert fstr == result
 
     fstr = get_standard_freq('5Q')
     assert fstr == get_standard_freq('5q')
-    assert fstr == get_standard_freq('5QuarTer')
+
+    with tm.assert_produces_warning(FutureWarning):
+        result = get_standard_freq('5QuarTer')
+    assert fstr == result
+
     assert fstr == get_standard_freq(('q', 5))