REF: is_subperiod, is_superperiod out of libfreqs

pandas/_libs/tslibs/frequencies.pyx

@@ -5,9 +5,7 @@ cnp.import_array()
 
 from pandas._libs.tslibs.util cimport is_integer_object
 
-from pandas._libs.tslibs.ccalendar cimport c_MONTH_NUMBERS
 from pandas._libs.tslibs.offsets cimport is_offset_object
-from pandas._libs.tslibs.parsing cimport get_rule_month
 
 # ----------------------------------------------------------------------
 # Constants
@@ -333,161 +331,3 @@ cpdef int get_to_timestamp_base(int base):
     elif FreqGroup.FR_HR <= base <= FreqGroup.FR_SEC:
         return FreqGroup.FR_SEC
     return base
-
-
-# ----------------------------------------------------------------------
-# Frequency comparison
-
-def is_subperiod(source, target) -> bint:
-    """
-    Returns True if downsampling is possible between source and target
-    frequencies
-
-    Parameters
-    ----------
-    source : string or DateOffset
-        Frequency converting from
-    target : string or DateOffset
-        Frequency converting to
-
-    Returns
-    -------
-    is_subperiod : boolean
-    """
-
-    if target is None or source is None:
-        return False
-    source = _maybe_coerce_freq(source)
-    target = _maybe_coerce_freq(target)
-
-    if _is_annual(target):
-        if _is_quarterly(source):
-            return _quarter_months_conform(get_rule_month(source),
-                                           get_rule_month(target))
-        return source in {'D', 'C', 'B', 'M', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif _is_quarterly(target):
-        return source in {'D', 'C', 'B', 'M', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif _is_monthly(target):
-        return source in {'D', 'C', 'B', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif _is_weekly(target):
-        return source in {target, 'D', 'C', 'B', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif target == 'B':
-        return source in {'B', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif target == 'C':
-        return source in {'C', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif target == 'D':
-        return source in {'D', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif target == 'H':
-        return source in {'H', 'T', 'S', 'L', 'U', 'N'}
-    elif target == 'T':
-        return source in {'T', 'S', 'L', 'U', 'N'}
-    elif target == 'S':
-        return source in {'S', 'L', 'U', 'N'}
-    elif target == 'L':
-        return source in {'L', 'U', 'N'}
-    elif target == 'U':
-        return source in {'U', 'N'}
-    elif target == 'N':
-        return source in {'N'}
-
-
-def is_superperiod(source, target) -> bint:
-    """
-    Returns True if upsampling is possible between source and target
-    frequencies
-
-    Parameters
-    ----------
-    source : string
-        Frequency converting from
-    target : string
-        Frequency converting to
-
-    Returns
-    -------
-    is_superperiod : boolean
-    """
-    if target is None or source is None:
-        return False
-    source = _maybe_coerce_freq(source)
-    target = _maybe_coerce_freq(target)
-
-    if _is_annual(source):
-        if _is_annual(target):
-            return get_rule_month(source) == get_rule_month(target)
-
-        if _is_quarterly(target):
-            smonth = get_rule_month(source)
-            tmonth = get_rule_month(target)
-            return _quarter_months_conform(smonth, tmonth)
-        return target in {'D', 'C', 'B', 'M', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif _is_quarterly(source):
-        return target in {'D', 'C', 'B', 'M', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif _is_monthly(source):
-        return target in {'D', 'C', 'B', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif _is_weekly(source):
-        return target in {source, 'D', 'C', 'B', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif source == 'B':
-        return target in {'D', 'C', 'B', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif source == 'C':
-        return target in {'D', 'C', 'B', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif source == 'D':
-        return target in {'D', 'C', 'B', 'H', 'T', 'S', 'L', 'U', 'N'}
-    elif source == 'H':
-        return target in {'H', 'T', 'S', 'L', 'U', 'N'}
-    elif source == 'T':
-        return target in {'T', 'S', 'L', 'U', 'N'}
-    elif source == 'S':
-        return target in {'S', 'L', 'U', 'N'}
-    elif source == 'L':
-        return target in {'L', 'U', 'N'}
-    elif source == 'U':
-        return target in {'U', 'N'}
-    elif source == 'N':
-        return target in {'N'}
-
-
-cdef str _maybe_coerce_freq(code):
-    """ we might need to coerce a code to a rule_code
-    and uppercase it
-
-    Parameters
-    ----------
-    source : string or DateOffset
-        Frequency converting from
-
-    Returns
-    -------
-    code : string
-    """
-    assert code is not None
-    if is_offset_object(code):
-        # i.e. isinstance(code, DateOffset):
-        code = code.rule_code
-    return code.upper()
-
-
-cdef bint _quarter_months_conform(str source, str target):
-    snum = c_MONTH_NUMBERS[source]
-    tnum = c_MONTH_NUMBERS[target]
-    return snum % 3 == tnum % 3
-
-
-cdef bint _is_annual(str rule):
-    rule = rule.upper()
-    return rule == 'A' or rule.startswith('A-')
-
-
-cdef bint _is_quarterly(str rule):
-    rule = rule.upper()
-    return rule == 'Q' or rule.startswith('Q-') or rule.startswith('BQ')
-
-
-cdef bint _is_monthly(str rule):
-    rule = rule.upper()
-    return rule == 'M' or rule == 'BM'
-
-
-cdef bint _is_weekly(str rule):
-    rule = rule.upper()
-    return rule == 'W' or rule.startswith('W-')

pandas/core/resample.py

@@ -7,7 +7,6 @@
 
 from pandas._libs import lib
 from pandas._libs.tslibs import NaT, Period, Timedelta, Timestamp
-from pandas._libs.tslibs.frequencies import is_subperiod, is_superperiod
 from pandas._libs.tslibs.period import IncompatibleFrequency
 from pandas._typing import TimedeltaConvertibleTypes, TimestampConvertibleTypes
 from pandas.compat.numpy import function as nv
@@ -29,7 +28,7 @@
 from pandas.core.indexes.period import PeriodIndex, period_range
 from pandas.core.indexes.timedeltas import TimedeltaIndex, timedelta_range
 
-from pandas.tseries.frequencies import to_offset
+from pandas.tseries.frequencies import is_subperiod, is_superperiod, to_offset
 from pandas.tseries.offsets import DateOffset, Day, Nano, Tick
 
 _shared_docs_kwargs: Dict[str, str] = dict()
@@ -1709,7 +1708,7 @@ def _get_timestamp_range_edges(
                 origin = origin.tz_localize(None)
 
         first, last = _adjust_dates_anchored(
-            first, last, freq, closed=closed, origin=origin, offset=offset,
+            first, last, freq, closed=closed, origin=origin, offset=offset
         )
         if isinstance(freq, Day):
             first = first.tz_localize(index_tz)
@@ -1771,7 +1770,7 @@ def _get_period_range_edges(
     adjust_last = freq.is_on_offset(last)
 
     first, last = _get_timestamp_range_edges(
-        first, last, freq, closed=closed, origin=origin, offset=offset,
+        first, last, freq, closed=closed, origin=origin, offset=offset
     )
 
     first = (first + int(adjust_first) * freq).to_period(freq)

pandas/plotting/_matplotlib/timeseries.py

@@ -5,13 +5,7 @@
 
 import numpy as np
 
-from pandas._libs.tslibs.frequencies import (
-    FreqGroup,
-    base_and_stride,
-    get_freq_code,
-    is_subperiod,
-    is_superperiod,
-)
+from pandas._libs.tslibs.frequencies import FreqGroup, base_and_stride, get_freq_code
 from pandas._libs.tslibs.period import Period
 
 from pandas.core.dtypes.generic import (
@@ -27,6 +21,7 @@
     TimeSeries_TimedeltaFormatter,
 )
 import pandas.tseries.frequencies as frequencies
+from pandas.tseries.frequencies import is_subperiod, is_superperiod
 from pandas.tseries.offsets import DateOffset
 
 # ---------------------------------------------------------------------

pandas/tests/tslibs/test_libfrequencies.py

@@ -1,14 +1,10 @@
 import pytest
 
-from pandas._libs.tslibs.frequencies import (
-    INVALID_FREQ_ERR_MSG,
-    _period_str_to_code,
-    is_subperiod,
-    is_superperiod,
-)
+from pandas._libs.tslibs.frequencies import INVALID_FREQ_ERR_MSG, _period_str_to_code
 from pandas._libs.tslibs.parsing import get_rule_month
 
 from pandas.tseries import offsets
+from pandas.tseries.frequencies import is_subperiod, is_superperiod  # TODO: move tests
 
 
 @pytest.mark.parametrize(