preserving freq without patching

pandas/core/algorithms.py

@@ -867,6 +867,26 @@ def value_counts_internal(
  Series,
  )
 
+ def _preserve_freq(original_values, result_index):
+ freq = getattr(original_values, "freq", None)
+
+ if (
+ freq is not None
+ and type(original_values) is type(result_index)
+ and len(result_index) == len(original_values)
+ and result_index.equals(original_values)
+ ):
+ try:
+ # Rebuild index with freq using the same constructor
+ return type(result_index)(
+ result_index._data, freq=freq, name=result_index.name
+ )
+ except (TypeError, ValueError):
+ # If reconstruction fails, return original index
+ pass
+
+ return result_index
+
  index_name = getattr(values, "name", None)
  name = "proportion" if normalize else "count"
 
@@ -929,6 +949,15 @@ def value_counts_internal(
  # Starting in 3.0, we no longer perform dtype inference on the
  # Index object we construct here, xref GH#56161
  idx = Index(keys, dtype=keys.dtype, name=index_name)
+
+ if (
+ bins is None
+ and not sort
+ and hasattr(values, "freq")
+ and values.freq is not None
+ ):
+ idx = _preserve_freq(values, idx)
+
  result = Series(counts, index=idx, name=name, copy=False)
 
  if sort:
@@ -937,36 +966,6 @@ def value_counts_internal(
  if normalize:
  result = result / counts.sum()
 
- # freq patching for DatetimeIndex, TimedeltaIndex
- try:
- from pandas import (
- DatetimeIndex,
- TimedeltaIndex,
- )
-
- if (
- bins is None
- and not sort
- and isinstance(values, (DatetimeIndex, TimedeltaIndex))
- and values.freq is not None
- and isinstance(result.index, (DatetimeIndex, TimedeltaIndex))
- and len(result.index) == len(values)
- and result.index.equals(values)
- ):
- base_freq = values.freq
- # Rebuild the index with the original freq; name preserved.
- if isinstance(result.index, DatetimeIndex):
- result.index = DatetimeIndex(
- result.index._data, freq=base_freq, name=result.index.name
- )
- else: # TimedeltaIndex
- result.index = TimedeltaIndex(
- result.index._data, freq=base_freq, name=result.index.name
- )
- except Exception:
- # If freq patching fails, does not affect value_counts
- pass
-
  return result