CLN: remove Resolution.get_stride_from_decimal; rename (#34515)

Author: jbrockmendel

pandas/_libs/tslibs/offsets.pyx

@@ -762,7 +762,7 @@ cdef class Tick(SingleConstructorOffset):
             return Micro(self.n * 1000)
         if type(self) is Micro:
             return Nano(self.n * 1000)
-        raise NotImplementedError(type(self))
+        raise ValueError("Could not convert to integer offset at any resolution")
 
     # --------------------------------------------------------------------
 

pandas/_libs/tslibs/resolution.pyx

@@ -27,16 +27,6 @@ cdef:
     int RESO_HR = 5
     int RESO_DAY = 6
 
-reso_str_bump_map = {
-    "D": "H",
-    "H": "T",
-    "T": "S",
-    "S": "L",
-    "L": "U",
-    "U": "N",
-    "N": None,
-}
-
 _abbrev_to_attrnames = {v: k for k, v in attrname_to_abbrevs.items()}
 
 _reso_str_map = {
@@ -168,19 +158,19 @@ class Resolution(Enum):
         return _reso_str_map[reso.value]
 
     @classmethod
-    def get_reso(cls, resostr: str) -> "Resolution":
+    def from_attrname(cls, attrname: str) -> "Resolution":
         """
         Return resolution str against resolution code.
 
         Examples
         --------
-        >>> Resolution.get_reso('second')
+        >>> Resolution.from_attrname('second')
         2
 
-        >>> Resolution.get_reso('second') == Resolution.RESO_SEC
+        >>> Resolution.from_attrname('second') == Resolution.RESO_SEC
         True
         """
-        return cls(_str_reso_map[resostr])
+        return cls(_str_reso_map[attrname])
 
     @classmethod
     def get_attrname_from_abbrev(cls, freq: str) -> str:
@@ -209,47 +199,7 @@ class Resolution(Enum):
         >>> Resolution.get_reso_from_freq('H') == Resolution.RESO_HR
         True
         """
-        return cls.get_reso(cls.get_attrname_from_abbrev(freq))
-
-    @classmethod
-    def get_stride_from_decimal(cls, value: float, freq: str):
-        """
-        Convert freq with decimal stride into a higher freq with integer stride
-
-        Parameters
-        ----------
-        value : float
-        freq : str
-            Frequency string
-
-        Raises
-        ------
-        ValueError
-            If the float cannot be converted to an integer at any resolution.
-
-        Examples
-        --------
-        >>> Resolution.get_stride_from_decimal(1.5, 'T')
-        (90, 'S')
-
-        >>> Resolution.get_stride_from_decimal(1.04, 'H')
-        (3744, 'S')
-
-        >>> Resolution.get_stride_from_decimal(1, 'D')
-        (1, 'D')
-        """
-        if np.isclose(value % 1, 0):
-            return int(value), freq
-        else:
-            start_reso = cls.get_reso_from_freq(freq)
-            if start_reso.value == 0:
-                raise ValueError(
-                    "Could not convert to integer offset at any resolution"
-                )
-
-            next_value = _reso_mult_map[start_reso.value] * value
-            next_name = reso_str_bump_map[freq]
-            return cls.get_stride_from_decimal(next_value, next_name)
+        return cls.from_attrname(cls.get_attrname_from_abbrev(freq))
 
 
 # ----------------------------------------------------------------------

pandas/core/indexes/datetimes.py

@@ -525,7 +525,7 @@ def _validate_partial_date_slice(self, reso: str):
         if (
             self.is_monotonic
             and reso in ["day", "hour", "minute", "second"]
-            and self._resolution >= libresolution.Resolution.get_reso(reso)
+            and self._resolution >= libresolution.Resolution.from_attrname(reso)
         ):
             # These resolution/monotonicity validations came from GH3931,
             # GH3452 and GH2369.

pandas/tests/tseries/frequencies/test_freq_code.py

@@ -10,6 +10,7 @@
 )
 from pandas._libs.tslibs.resolution import Resolution as _reso
 
+from pandas.tseries.frequencies import to_offset
 import pandas.tseries.offsets as offsets
 
 
@@ -116,7 +117,8 @@ def test_get_freq_roundtrip(freq):
 
 @pytest.mark.parametrize("freq", ["D", "H", "T", "S", "L", "U"])
 def test_get_freq_roundtrip2(freq):
-    result = _attrname_to_abbrevs[_reso.get_str(_reso.get_reso_from_freq(freq))]
+    obj = _reso.get_reso_from_freq(freq)
+    result = _attrname_to_abbrevs[_reso.get_str(obj)]
     assert freq == result
 
 
@@ -133,7 +135,9 @@ def test_get_freq_roundtrip2(freq):
 )
 def test_resolution_bumping(args, expected):
     # see gh-14378
-    assert _reso.get_stride_from_decimal(*args) == expected
+    off = to_offset(str(args[0]) + args[1])
+    assert off.n == expected[0]
+    assert off._prefix == expected[1]
 
 
 @pytest.mark.parametrize(
@@ -145,10 +149,10 @@ def test_resolution_bumping(args, expected):
     ],
 )
 def test_cat(args):
-    msg = "Could not convert to integer offset at any resolution"
+    msg = "Invalid frequency"
 
     with pytest.raises(ValueError, match=msg):
-        _reso.get_stride_from_decimal(*args)
+        to_offset(str(args[0]) + args[1])
 
 
 @pytest.mark.parametrize(