DEPR: Remove legacy offsets

Follow-up of pandas-dev#10951.
Remove legacy offsets deprecated in 0.17.0.

Author: sinhrks <[email protected]>

Closes pandas-dev#13590 from sinhrks/depr_legacy_offset and squashes the following commits:

2593b1f [sinhrks] DEPR: Remove legacy offsets

Author: sinhrks

doc/source/timeseries.rst

@@ -752,7 +752,7 @@ calculate significantly slower and will raise a ``PerformanceWarning``
    rng + BQuarterEnd()
 
 
-.. _timeseries.alias:
+.. _timeseries.custombusinessdays:
 
 Custom Business Days (Experimental)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -953,6 +953,8 @@ You can use keyword arguments suported by either ``BusinessHour`` and ``CustomBu
     # Monday is skipped because it's a holiday, business hour starts from 10:00
     dt + bhour_mon * 2
 
+.. _timeseries.alias:
+
 Offset Aliases
 ~~~~~~~~~~~~~~
 
@@ -1103,48 +1105,6 @@ it is rolled forward to the next anchor point.
    pd.Timestamp('2014-01-01') + MonthBegin(n=0)
    pd.Timestamp('2014-01-31') + MonthEnd(n=0)
 
-.. _timeseries.legacyaliases:
-
-Legacy 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"
-    :widths: 15, 65
-
-    "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"
-    "Q\@JAN", "BQ\-JAN"
-    "Q\@FEB", "BQ\-FEB"
-    "Q\@MAR", "BQ\-MAR"
-    "A\@JAN", "BA\-JAN"
-    "A\@FEB", "BA\-FEB"
-    "A\@MAR", "BA\-MAR"
-    "A\@APR", "BA\-APR"
-    "A\@MAY", "BA\-MAY"
-    "A\@JUN", "BA\-JUN"
-    "A\@JUL", "BA\-JUL"
-    "A\@AUG", "BA\-AUG"
-    "A\@SEP", "BA\-SEP"
-    "A\@OCT", "BA\-OCT"
-    "A\@NOV", "BA\-NOV"
-    "A\@DEC", "BA\-DEC"
-
-
-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
-``ms`` versus the new offset alias for month start ``MS``. This means that
-offset alias parsing is case sensitive.
-
 .. _timeseries.holiday:
 
 Holidays / Holiday Calendars

doc/source/whatsnew/v0.19.0.txt

@@ -510,6 +510,17 @@ Removal of prior version deprecations/changes
 - ``DataFrame.to_dict()`` has dropped the ``outtype`` parameter in favor of ``orient`` (:issue:`13627`, :issue:`8486`)
 - ``pd.Categorical`` has dropped the ``levels`` attribute in favour of ``categories`` (:issue:`8376`)
 
+- Removal of the legacy time rules (offset aliases), deprecated since 0.17.0 (this has been alias since 0.8.0) (:issue:`13590`)
+
+  Previous Behavior:
+
+  .. code-block:: ipython
+
+     In [2]: pd.date_range('2016-07-01', freq='W@MON', periods=3)
+     pandas/tseries/frequencies.py:465: FutureWarning: Freq "W@MON" is deprecated, use "W-MON" as alternative.
+     Out[2]: DatetimeIndex(['2016-07-04', '2016-07-11', '2016-07-18'], dtype='datetime64[ns]', freq='W-MON')
+
+  Now legacy time rules raises ``ValueError``. For the list of currently supported offsets, see :ref:`here <timeseries.alias>`
 
 .. _whatsnew_0190.performance:
 

pandas/tseries/frequencies.py

@@ -1,5 +1,5 @@
 from datetime import timedelta
-from pandas.compat import range, long, zip
+from pandas.compat import long, zip
 from pandas import compat
 import re
 import warnings
@@ -356,34 +356,6 @@ def get_period_alias(offset_str):
     """ alias to closest period strings BQ->Q etc"""
     return _offset_to_period_map.get(offset_str, None)
 
-_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',
-    'Q@JAN': 'BQ-JAN',
-    'Q@FEB': 'BQ-FEB',
-    'Q@MAR': 'BQ-MAR',
-    'A@JAN': 'BA-JAN',
-    'A@FEB': 'BA-FEB',
-    'A@MAR': 'BA-MAR',
-    'A@APR': 'BA-APR',
-    'A@MAY': 'BA-MAY',
-    'A@JUN': 'BA-JUN',
-    'A@JUL': 'BA-JUL',
-    'A@AUG': 'BA-AUG',
-    'A@SEP': 'BA-SEP',
-    'A@OCT': 'BA-OCT',
-    'A@NOV': 'BA-NOV',
-    'A@DEC': 'BA-DEC',
-}
 
 _lite_rule_alias = {
     'W': 'W-SUN',
@@ -401,17 +373,6 @@ def get_period_alias(offset_str):
     'ns': 'N'
 }
 
-# TODO: Can this be killed?
-for _i, _weekday in enumerate(['MON', 'TUE', 'WED', 'THU', 'FRI']):
-    for _iweek in range(4):
-        _name = 'WOM-%d%s' % (_iweek + 1, _weekday)
-        _rule_aliases[_name.replace('-', '@')] = _name
-
-# 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))))
 
 _name_to_offset_map = {'days': Day(1),
                        'hours': Hour(1),
@@ -422,6 +383,9 @@ def get_period_alias(offset_str):
                        'nanoseconds': Nano(1)}
 
 
+_INVALID_FREQ_ERROR = "Invalid frequency: {0}"
+
+
 def to_offset(freqstr):
     """
     Return DateOffset object from string representation or
@@ -460,7 +424,7 @@ def to_offset(freqstr):
                     else:
                         delta = delta + offset
         except Exception:
-            raise ValueError("Could not evaluate %s" % freqstr)
+            raise ValueError(_INVALID_FREQ_ERROR.format(freqstr))
 
     else:
         delta = None
@@ -479,10 +443,10 @@ def to_offset(freqstr):
                 else:
                     delta = delta + offset
         except Exception:
-            raise ValueError("Could not evaluate %s" % freqstr)
+            raise ValueError(_INVALID_FREQ_ERROR.format(freqstr))
 
     if delta is None:
-        raise ValueError('Unable to understand %s as a frequency' % freqstr)
+        raise ValueError(_INVALID_FREQ_ERROR.format(freqstr))
 
     return delta
 
@@ -526,9 +490,6 @@ 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
@@ -539,27 +500,9 @@ def get_offset(name):
     """
     if name not in _dont_uppercase:
         name = name.upper()
-
-        if name in _rule_aliases:
-            new = _rule_aliases[name]
-            warnings.warn(_LEGACY_FREQ_WARNING.format(name, new),
-                          FutureWarning, stacklevel=2)
-            name = new
-        elif name.lower() in _rule_aliases:
-            new = _rule_aliases[name.lower()]
-            warnings.warn(_LEGACY_FREQ_WARNING.format(name, new),
-                          FutureWarning, stacklevel=2)
-            name = new
-
         name = _lite_rule_alias.get(name, name)
         name = _lite_rule_alias.get(name.lower(), name)
-
     else:
-        if name in _rule_aliases:
-            new = _rule_aliases[name]
-            warnings.warn(_LEGACY_FREQ_WARNING.format(name, new),
-                          FutureWarning, stacklevel=2)
-            name = new
         name = _lite_rule_alias.get(name, name)
 
     if name not in _offset_map:
@@ -571,7 +514,7 @@ def get_offset(name):
             offset = klass._from_name(*split[1:])
         except (ValueError, TypeError, KeyError):
             # bad prefix or suffix
-            raise ValueError('Bad rule name requested: %s.' % name)
+            raise ValueError(_INVALID_FREQ_ERROR.format(name))
         # cache
         _offset_map[name] = offset
     # do not return cache because it's mutable
@@ -595,17 +538,6 @@ def get_offset_name(offset):
     return offset.freqstr
 
 
-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)
-
-
 def get_standard_freq(freq):
     """
     Return the standardized frequency string
@@ -796,36 +728,18 @@ def _period_alias_dictionary():
 
 
 def _period_str_to_code(freqstr):
-    # hack
-    if freqstr in _rule_aliases:
-        new = _rule_aliases[freqstr]
-        warnings.warn(_LEGACY_FREQ_WARNING.format(freqstr, new),
-                      FutureWarning, stacklevel=3)
-        freqstr = new
     freqstr = _lite_rule_alias.get(freqstr, freqstr)
 
     if freqstr not in _dont_uppercase:
         lower = freqstr.lower()
-        if lower in _rule_aliases:
-            new = _rule_aliases[lower]
-            warnings.warn(_LEGACY_FREQ_WARNING.format(lower, new),
-                          FutureWarning, stacklevel=3)
-            freqstr = new
         freqstr = _lite_rule_alias.get(lower, freqstr)
 
+    if freqstr not in _dont_uppercase:
+        freqstr = freqstr.upper()
     try:
-        if freqstr not in _dont_uppercase:
-            freqstr = freqstr.upper()
         return _period_code_map[freqstr]
     except KeyError:
-        try:
-            alias = _period_alias_dict[freqstr]
-            warnings.warn(_LEGACY_FREQ_WARNING.format(freqstr, alias),
-                          FutureWarning, stacklevel=3)
-        except KeyError:
-            raise ValueError("Unknown freqstr: %s" % freqstr)
-
-        return _period_code_map[alias]
+        raise ValueError(_INVALID_FREQ_ERROR.format(freqstr))
 
 
 def infer_freq(index, warn=True):

pandas/tseries/tests/test_base.py

@@ -160,9 +160,11 @@ def test_round(self):
             tm.assert_index_equal(rng.round(freq='H'), expected_rng)
             self.assertEqual(elt.round(freq='H'), expected_elt)
 
-            msg = "Could not evaluate foo"
-            tm.assertRaisesRegexp(ValueError, msg, rng.round, freq='foo')
-            tm.assertRaisesRegexp(ValueError, msg, elt.round, freq='foo')
+            msg = pd.tseries.frequencies._INVALID_FREQ_ERROR
+            with tm.assertRaisesRegexp(ValueError, msg):
+                rng.round(freq='foo')
+            with tm.assertRaisesRegexp(ValueError, msg):
+                elt.round(freq='foo')
 
             msg = "<MonthEnd> is a non-fixed frequency"
             tm.assertRaisesRegexp(ValueError, msg, rng.round, freq='M')
@@ -847,9 +849,11 @@ def test_round(self):
         tm.assert_index_equal(td.round(freq='H'), expected_rng)
         self.assertEqual(elt.round(freq='H'), expected_elt)
 
-        msg = "Could not evaluate foo"
-        tm.assertRaisesRegexp(ValueError, msg, td.round, freq='foo')
-        tm.assertRaisesRegexp(ValueError, msg, elt.round, freq='foo')
+        msg = pd.tseries.frequencies._INVALID_FREQ_ERROR
+        with self.assertRaisesRegexp(ValueError, msg):
+            td.round(freq='foo')
+        with tm.assertRaisesRegexp(ValueError, msg):
+            elt.round(freq='foo')
 
         msg = "<MonthEnd> is a non-fixed frequency"
         tm.assertRaisesRegexp(ValueError, msg, td.round, freq='M')

pandas/tseries/tests/test_frequencies.py

@@ -245,10 +245,10 @@ def _assert_depr(freq, expected, aliases):
         assert isinstance(aliases, list)
         assert (frequencies._period_str_to_code(freq) == expected)
 
+        msg = frequencies._INVALID_FREQ_ERROR
         for alias in aliases:
-            with tm.assert_produces_warning(FutureWarning,
-                                            check_stacklevel=False):
-                assert (frequencies._period_str_to_code(alias) == expected)
+            with tm.assertRaisesRegexp(ValueError, msg):
+                frequencies._period_str_to_code(alias)
 
     _assert_depr("M", 3000, ["MTH", "MONTH", "MONTHLY"])
 
@@ -699,8 +699,9 @@ def test_series(self):
             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,
-                                            check_stacklevel=False):
+
+            msg = frequencies._INVALID_FREQ_ERROR
+            with tm.assertRaisesRegexp(ValueError, msg):
                 s = Series(period_range('2013', periods=10, freq=freq))
             self.assertRaises(TypeError, lambda: frequencies.infer_freq(s))
 
@@ -715,17 +716,23 @@ def test_series(self):
         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,
-                                            check_stacklevel=False):
-                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)
+        freqs = ['WEEKDAY', 'EOM', 'W@MON', 'W@TUE', 'W@WED', 'W@THU',
+                 'W@FRI', 'W@SAT', 'W@SUN', 'Q@JAN', 'Q@FEB', 'Q@MAR',
+                 'A@JAN', 'A@FEB', 'A@MAR', 'A@APR', 'A@MAY', 'A@JUN',
+                 'A@JUL', 'A@AUG', 'A@SEP', 'A@OCT', 'A@NOV', 'A@DEC',
+                 'WOM@1MON', 'WOM@2MON', 'WOM@3MON', 'WOM@4MON',
+                 'WOM@1TUE', 'WOM@2TUE', 'WOM@3TUE', 'WOM@4TUE',
+                 'WOM@1WED', 'WOM@2WED', 'WOM@3WED', 'WOM@4WED',
+                 'WOM@1THU', 'WOM@2THU', 'WOM@3THU', 'WOM@4THU'
+                 'WOM@1FRI', 'WOM@2FRI', 'WOM@3FRI', 'WOM@4FRI']
+
+        msg = frequencies._INVALID_FREQ_ERROR
+        for freq in freqs:
+            with tm.assertRaisesRegexp(ValueError, msg):
+                frequencies.get_offset(freq)
+
+            with tm.assertRaisesRegexp(ValueError, msg):
+                date_range('2011-01-01', periods=5, freq=freq)
 
 
 MONTHS = ['JAN', 'FEB', 'MAR', 'APR', 'MAY', 'JUN', 'JUL', 'AUG', 'SEP', 'OCT',