Updated script that can be controled by Nodejs web app

lib/python3.13/site-packages/pandas/core/indexes/accessors.py

@@ -0,0 +1,643 @@
+"""
+datetimelike delegation
+"""
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING,
+    cast,
+)
+import warnings
+
+import numpy as np
+
+from pandas._libs import lib
+from pandas.util._exceptions import find_stack_level
+
+from pandas.core.dtypes.common import (
+    is_integer_dtype,
+    is_list_like,
+)
+from pandas.core.dtypes.dtypes import (
+    ArrowDtype,
+    CategoricalDtype,
+    DatetimeTZDtype,
+    PeriodDtype,
+)
+from pandas.core.dtypes.generic import ABCSeries
+
+from pandas.core.accessor import (
+    PandasDelegate,
+    delegate_names,
+)
+from pandas.core.arrays import (
+    DatetimeArray,
+    PeriodArray,
+    TimedeltaArray,
+)
+from pandas.core.arrays.arrow.array import ArrowExtensionArray
+from pandas.core.base import (
+    NoNewAttributesMixin,
+    PandasObject,
+)
+from pandas.core.indexes.datetimes import DatetimeIndex
+from pandas.core.indexes.timedeltas import TimedeltaIndex
+
+if TYPE_CHECKING:
+    from pandas import (
+        DataFrame,
+        Series,
+    )
+
+
+class Properties(PandasDelegate, PandasObject, NoNewAttributesMixin):
+    _hidden_attrs = PandasObject._hidden_attrs | {
+        "orig",
+        "name",
+    }
+
+    def __init__(self, data: Series, orig) -> None:
+        if not isinstance(data, ABCSeries):
+            raise TypeError(
+                f"cannot convert an object of type {type(data)} to a datetimelike index"
+            )
+
+        self._parent = data
+        self.orig = orig
+        self.name = getattr(data, "name", None)
+        self._freeze()
+
+    def _get_values(self):
+        data = self._parent
+        if lib.is_np_dtype(data.dtype, "M"):
+            return DatetimeIndex(data, copy=False, name=self.name)
+
+        elif isinstance(data.dtype, DatetimeTZDtype):
+            return DatetimeIndex(data, copy=False, name=self.name)
+
+        elif lib.is_np_dtype(data.dtype, "m"):
+            return TimedeltaIndex(data, copy=False, name=self.name)
+
+        elif isinstance(data.dtype, PeriodDtype):
+            return PeriodArray(data, copy=False)
+
+        raise TypeError(
+            f"cannot convert an object of type {type(data)} to a datetimelike index"
+        )
+
+    def _delegate_property_get(self, name: str):
+        from pandas import Series
+
+        values = self._get_values()
+
+        result = getattr(values, name)
+
+        # maybe need to upcast (ints)
+        if isinstance(result, np.ndarray):
+            if is_integer_dtype(result):
+                result = result.astype("int64")
+        elif not is_list_like(result):
+            return result
+
+        result = np.asarray(result)
+
+        if self.orig is not None:
+            index = self.orig.index
+        else:
+            index = self._parent.index
+        # return the result as a Series
+        result = Series(result, index=index, name=self.name).__finalize__(self._parent)
+
+        # setting this object will show a SettingWithCopyWarning/Error
+        result._is_copy = (
+            "modifications to a property of a datetimelike "
+            "object are not supported and are discarded. "
+            "Change values on the original."
+        )
+
+        return result
+
+    def _delegate_property_set(self, name: str, value, *args, **kwargs):
+        raise ValueError(
+            "modifications to a property of a datetimelike object are not supported. "
+            "Change values on the original."
+        )
+
+    def _delegate_method(self, name: str, *args, **kwargs):
+        from pandas import Series
+
+        values = self._get_values()
+
+        method = getattr(values, name)
+        result = method(*args, **kwargs)
+
+        if not is_list_like(result):
+            return result
+
+        result = Series(result, index=self._parent.index, name=self.name).__finalize__(
+            self._parent
+        )
+
+        # setting this object will show a SettingWithCopyWarning/Error
+        result._is_copy = (
+            "modifications to a method of a datetimelike "
+            "object are not supported and are discarded. "
+            "Change values on the original."
+        )
+
+        return result
+
+
+@delegate_names(
+    delegate=ArrowExtensionArray,
+    accessors=TimedeltaArray._datetimelike_ops,
+    typ="property",
+    accessor_mapping=lambda x: f"_dt_{x}",
+    raise_on_missing=False,
+)
+@delegate_names(
+    delegate=ArrowExtensionArray,
+    accessors=TimedeltaArray._datetimelike_methods,
+    typ="method",
+    accessor_mapping=lambda x: f"_dt_{x}",
+    raise_on_missing=False,
+)
+@delegate_names(
+    delegate=ArrowExtensionArray,
+    accessors=DatetimeArray._datetimelike_ops,
+    typ="property",
+    accessor_mapping=lambda x: f"_dt_{x}",
+    raise_on_missing=False,
+)
+@delegate_names(
+    delegate=ArrowExtensionArray,
+    accessors=DatetimeArray._datetimelike_methods,
+    typ="method",
+    accessor_mapping=lambda x: f"_dt_{x}",
+    raise_on_missing=False,
+)
+class ArrowTemporalProperties(PandasDelegate, PandasObject, NoNewAttributesMixin):
+    def __init__(self, data: Series, orig) -> None:
+        if not isinstance(data, ABCSeries):
+            raise TypeError(
+                f"cannot convert an object of type {type(data)} to a datetimelike index"
+            )
+
+        self._parent = data
+        self._orig = orig
+        self._freeze()
+
+    def _delegate_property_get(self, name: str):
+        if not hasattr(self._parent.array, f"_dt_{name}"):
+            raise NotImplementedError(
+                f"dt.{name} is not supported for {self._parent.dtype}"
+            )
+        result = getattr(self._parent.array, f"_dt_{name}")
+
+        if not is_list_like(result):
+            return result
+
+        if self._orig is not None:
+            index = self._orig.index
+        else:
+            index = self._parent.index
+        # return the result as a Series, which is by definition a copy
+        result = type(self._parent)(
+            result, index=index, name=self._parent.name
+        ).__finalize__(self._parent)
+
+        return result
+
+    def _delegate_method(self, name: str, *args, **kwargs):
+        if not hasattr(self._parent.array, f"_dt_{name}"):
+            raise NotImplementedError(
+                f"dt.{name} is not supported for {self._parent.dtype}"
+            )
+
+        result = getattr(self._parent.array, f"_dt_{name}")(*args, **kwargs)
+
+        if self._orig is not None:
+            index = self._orig.index
+        else:
+            index = self._parent.index
+        # return the result as a Series, which is by definition a copy
+        result = type(self._parent)(
+            result, index=index, name=self._parent.name
+        ).__finalize__(self._parent)
+
+        return result
+
+    def to_pytimedelta(self):
+        return cast(ArrowExtensionArray, self._parent.array)._dt_to_pytimedelta()
+
+    def to_pydatetime(self):
+        # GH#20306
+        warnings.warn(
+            f"The behavior of {type(self).__name__}.to_pydatetime is deprecated, "
+            "in a future version this will return a Series containing python "
+            "datetime objects instead of an ndarray. To retain the old behavior, "
+            "call `np.array` on the result",
+            FutureWarning,
+            stacklevel=find_stack_level(),
+        )
+        return cast(ArrowExtensionArray, self._parent.array)._dt_to_pydatetime()
+
+    def isocalendar(self) -> DataFrame:
+        from pandas import DataFrame
+
+        result = (
+            cast(ArrowExtensionArray, self._parent.array)
+            ._dt_isocalendar()
+            ._pa_array.combine_chunks()
+        )
+        iso_calendar_df = DataFrame(
+            {
+                col: type(self._parent.array)(result.field(i))  # type: ignore[call-arg]
+                for i, col in enumerate(["year", "week", "day"])
+            }
+        )
+        return iso_calendar_df
+
+    @property
+    def components(self) -> DataFrame:
+        from pandas import DataFrame
+
+        components_df = DataFrame(
+            {
+                col: getattr(self._parent.array, f"_dt_{col}")
+                for col in [
+                    "days",
+                    "hours",
+                    "minutes",
+                    "seconds",
+                    "milliseconds",
+                    "microseconds",
+                    "nanoseconds",
+                ]
+            }
+        )
+        return components_df
+
+
+@delegate_names(
+    delegate=DatetimeArray,
+    accessors=DatetimeArray._datetimelike_ops + ["unit"],
+    typ="property",
+)
+@delegate_names(
+    delegate=DatetimeArray,
+    accessors=DatetimeArray._datetimelike_methods + ["as_unit"],
+    typ="method",
+)
+class DatetimeProperties(Properties):
+    """
+    Accessor object for datetimelike properties of the Series values.
+
+    Examples
+    --------
+    >>> seconds_series = pd.Series(pd.date_range("2000-01-01", periods=3, freq="s"))
+    >>> seconds_series
+    0   2000-01-01 00:00:00
+    1   2000-01-01 00:00:01
+    2   2000-01-01 00:00:02
+    dtype: datetime64[ns]
+    >>> seconds_series.dt.second
+    0    0
+    1    1
+    2    2
+    dtype: int32
+
+    >>> hours_series = pd.Series(pd.date_range("2000-01-01", periods=3, freq="h"))
+    >>> hours_series
+    0   2000-01-01 00:00:00
+    1   2000-01-01 01:00:00
+    2   2000-01-01 02:00:00
+    dtype: datetime64[ns]
+    >>> hours_series.dt.hour
+    0    0
+    1    1
+    2    2
+    dtype: int32
+
+    >>> quarters_series = pd.Series(pd.date_range("2000-01-01", periods=3, freq="QE"))
+    >>> quarters_series
+    0   2000-03-31
+    1   2000-06-30
+    2   2000-09-30
+    dtype: datetime64[ns]
+    >>> quarters_series.dt.quarter
+    0    1
+    1    2
+    2    3
+    dtype: int32
+
+    Returns a Series indexed like the original Series.
+    Raises TypeError if the Series does not contain datetimelike values.
+    """
+
+    def to_pydatetime(self) -> np.ndarray:
+        """
+        Return the data as an array of :class:`datetime.datetime` objects.
+
+        .. deprecated:: 2.1.0
+
+            The current behavior of dt.to_pydatetime is deprecated.
+            In a future version this will return a Series containing python
+            datetime objects instead of a ndarray.
+
+        Timezone information is retained if present.
+
+        .. warning::
+
+           Python's datetime uses microsecond resolution, which is lower than
+           pandas (nanosecond). The values are truncated.
+
+        Returns
+        -------
+        numpy.ndarray
+            Object dtype array containing native Python datetime objects.
+
+        See Also
+        --------
+        datetime.datetime : Standard library value for a datetime.
+
+        Examples
+        --------
+        >>> s = pd.Series(pd.date_range('20180310', periods=2))
+        >>> s
+        0   2018-03-10
+        1   2018-03-11
+        dtype: datetime64[ns]
+
+        >>> s.dt.to_pydatetime()
+        array([datetime.datetime(2018, 3, 10, 0, 0),
+               datetime.datetime(2018, 3, 11, 0, 0)], dtype=object)
+
+        pandas' nanosecond precision is truncated to microseconds.
+
+        >>> s = pd.Series(pd.date_range('20180310', periods=2, freq='ns'))
+        >>> s
+        0   2018-03-10 00:00:00.000000000
+        1   2018-03-10 00:00:00.000000001
+        dtype: datetime64[ns]
+
+        >>> s.dt.to_pydatetime()
+        array([datetime.datetime(2018, 3, 10, 0, 0),
+               datetime.datetime(2018, 3, 10, 0, 0)], dtype=object)
+        """
+        # GH#20306
+        warnings.warn(
+            f"The behavior of {type(self).__name__}.to_pydatetime is deprecated, "
+            "in a future version this will return a Series containing python "
+            "datetime objects instead of an ndarray. To retain the old behavior, "
+            "call `np.array` on the result",
+            FutureWarning,
+            stacklevel=find_stack_level(),
+        )
+        return self._get_values().to_pydatetime()
+
+    @property
+    def freq(self):
+        return self._get_values().inferred_freq
+
+    def isocalendar(self) -> DataFrame:
+        """
+        Calculate year, week, and day according to the ISO 8601 standard.
+
+        Returns
+        -------
+        DataFrame
+            With columns year, week and day.
+
+        See Also
+        --------
+        Timestamp.isocalendar : Function return a 3-tuple containing ISO year,
+            week number, and weekday for the given Timestamp object.
+        datetime.date.isocalendar : Return a named tuple object with
+            three components: year, week and weekday.
+
+        Examples
+        --------
+        >>> ser = pd.to_datetime(pd.Series(["2010-01-01", pd.NaT]))
+        >>> ser.dt.isocalendar()
+           year  week  day
+        0  2009    53     5
+        1  <NA>  <NA>  <NA>
+        >>> ser.dt.isocalendar().week
+        0      53
+        1    <NA>
+        Name: week, dtype: UInt32
+        """
+        return self._get_values().isocalendar().set_index(self._parent.index)
+
+
+@delegate_names(
+    delegate=TimedeltaArray, accessors=TimedeltaArray._datetimelike_ops, typ="property"
+)
+@delegate_names(
+    delegate=TimedeltaArray,
+    accessors=TimedeltaArray._datetimelike_methods,
+    typ="method",
+)
+class TimedeltaProperties(Properties):
+    """
+    Accessor object for datetimelike properties of the Series values.
+
+    Returns a Series indexed like the original Series.
+    Raises TypeError if the Series does not contain datetimelike values.
+
+    Examples
+    --------
+    >>> seconds_series = pd.Series(
+    ...     pd.timedelta_range(start="1 second", periods=3, freq="s")
+    ... )
+    >>> seconds_series
+    0   0 days 00:00:01
+    1   0 days 00:00:02
+    2   0 days 00:00:03
+    dtype: timedelta64[ns]
+    >>> seconds_series.dt.seconds
+    0    1
+    1    2
+    2    3
+    dtype: int32
+    """
+
+    def to_pytimedelta(self) -> np.ndarray:
+        """
+        Return an array of native :class:`datetime.timedelta` objects.
+
+        Python's standard `datetime` library uses a different representation
+        timedelta's. This method converts a Series of pandas Timedeltas
+        to `datetime.timedelta` format with the same length as the original
+        Series.
+
+        Returns
+        -------
+        numpy.ndarray
+            Array of 1D containing data with `datetime.timedelta` type.
+
+        See Also
+        --------
+        datetime.timedelta : A duration expressing the difference
+            between two date, time, or datetime.
+
+        Examples
+        --------
+        >>> s = pd.Series(pd.to_timedelta(np.arange(5), unit="d"))
+        >>> s
+        0   0 days
+        1   1 days
+        2   2 days
+        3   3 days
+        4   4 days
+        dtype: timedelta64[ns]
+
+        >>> s.dt.to_pytimedelta()
+        array([datetime.timedelta(0), datetime.timedelta(days=1),
+        datetime.timedelta(days=2), datetime.timedelta(days=3),
+        datetime.timedelta(days=4)], dtype=object)
+        """
+        return self._get_values().to_pytimedelta()
+
+    @property
+    def components(self):
+        """
+        Return a Dataframe of the components of the Timedeltas.
+
+        Returns
+        -------
+        DataFrame
+
+        Examples
+        --------
+        >>> s = pd.Series(pd.to_timedelta(np.arange(5), unit='s'))
+        >>> s
+        0   0 days 00:00:00
+        1   0 days 00:00:01
+        2   0 days 00:00:02
+        3   0 days 00:00:03
+        4   0 days 00:00:04
+        dtype: timedelta64[ns]
+        >>> s.dt.components
+           days  hours  minutes  seconds  milliseconds  microseconds  nanoseconds
+        0     0      0        0        0             0             0            0
+        1     0      0        0        1             0             0            0
+        2     0      0        0        2             0             0            0
+        3     0      0        0        3             0             0            0
+        4     0      0        0        4             0             0            0
+        """
+        return (
+            self._get_values()
+            .components.set_index(self._parent.index)
+            .__finalize__(self._parent)
+        )
+
+    @property
+    def freq(self):
+        return self._get_values().inferred_freq
+
+
+@delegate_names(
+    delegate=PeriodArray, accessors=PeriodArray._datetimelike_ops, typ="property"
+)
+@delegate_names(
+    delegate=PeriodArray, accessors=PeriodArray._datetimelike_methods, typ="method"
+)
+class PeriodProperties(Properties):
+    """
+    Accessor object for datetimelike properties of the Series values.
+
+    Returns a Series indexed like the original Series.
+    Raises TypeError if the Series does not contain datetimelike values.
+
+    Examples
+    --------
+    >>> seconds_series = pd.Series(
+    ...     pd.period_range(
+    ...         start="2000-01-01 00:00:00", end="2000-01-01 00:00:03", freq="s"
+    ...     )
+    ... )
+    >>> seconds_series
+    0    2000-01-01 00:00:00
+    1    2000-01-01 00:00:01
+    2    2000-01-01 00:00:02
+    3    2000-01-01 00:00:03
+    dtype: period[s]
+    >>> seconds_series.dt.second
+    0    0
+    1    1
+    2    2
+    3    3
+    dtype: int64
+
+    >>> hours_series = pd.Series(
+    ...     pd.period_range(start="2000-01-01 00:00", end="2000-01-01 03:00", freq="h")
+    ... )
+    >>> hours_series
+    0    2000-01-01 00:00
+    1    2000-01-01 01:00
+    2    2000-01-01 02:00
+    3    2000-01-01 03:00
+    dtype: period[h]
+    >>> hours_series.dt.hour
+    0    0
+    1    1
+    2    2
+    3    3
+    dtype: int64
+
+    >>> quarters_series = pd.Series(
+    ...     pd.period_range(start="2000-01-01", end="2000-12-31", freq="Q-DEC")
+    ... )
+    >>> quarters_series
+    0    2000Q1
+    1    2000Q2
+    2    2000Q3
+    3    2000Q4
+    dtype: period[Q-DEC]
+    >>> quarters_series.dt.quarter
+    0    1
+    1    2
+    2    3
+    3    4
+    dtype: int64
+    """
+
+
+class CombinedDatetimelikeProperties(
+    DatetimeProperties, TimedeltaProperties, PeriodProperties
+):
+    def __new__(cls, data: Series):  # pyright: ignore[reportInconsistentConstructor]
+        # CombinedDatetimelikeProperties isn't really instantiated. Instead
+        # we need to choose which parent (datetime or timedelta) is
+        # appropriate. Since we're checking the dtypes anyway, we'll just
+        # do all the validation here.
+
+        if not isinstance(data, ABCSeries):
+            raise TypeError(
+                f"cannot convert an object of type {type(data)} to a datetimelike index"
+            )
+
+        orig = data if isinstance(data.dtype, CategoricalDtype) else None
+        if orig is not None:
+            data = data._constructor(
+                orig.array,
+                name=orig.name,
+                copy=False,
+                dtype=orig._values.categories.dtype,
+                index=orig.index,
+            )
+
+        if isinstance(data.dtype, ArrowDtype) and data.dtype.kind in "Mm":
+            return ArrowTemporalProperties(data, orig)
+        if lib.is_np_dtype(data.dtype, "M"):
+            return DatetimeProperties(data, orig)
+        elif isinstance(data.dtype, DatetimeTZDtype):
+            return DatetimeProperties(data, orig)
+        elif lib.is_np_dtype(data.dtype, "m"):
+            return TimedeltaProperties(data, orig)
+        elif isinstance(data.dtype, PeriodDtype):
+            return PeriodProperties(data, orig)
+
+        raise AttributeError("Can only use .dt accessor with datetimelike values")

lib/python3.13/site-packages/pandas/core/indexes/api.py

@@ -0,0 +1,388 @@
+from __future__ import annotations
+
+import textwrap
+from typing import (
+    TYPE_CHECKING,
+    cast,
+)
+
+import numpy as np
+
+from pandas._libs import (
+    NaT,
+    lib,
+)
+from pandas.errors import InvalidIndexError
+
+from pandas.core.dtypes.cast import find_common_type
+
+from pandas.core.algorithms import safe_sort
+from pandas.core.indexes.base import (
+    Index,
+    _new_Index,
+    ensure_index,
+    ensure_index_from_sequences,
+    get_unanimous_names,
+)
+from pandas.core.indexes.category import CategoricalIndex
+from pandas.core.indexes.datetimes import DatetimeIndex
+from pandas.core.indexes.interval import IntervalIndex
+from pandas.core.indexes.multi import MultiIndex
+from pandas.core.indexes.period import PeriodIndex
+from pandas.core.indexes.range import RangeIndex
+from pandas.core.indexes.timedeltas import TimedeltaIndex
+
+if TYPE_CHECKING:
+    from pandas._typing import Axis
+_sort_msg = textwrap.dedent(
+    """\
+Sorting because non-concatenation axis is not aligned. A future version
+of pandas will change to not sort by default.
+
+To accept the future behavior, pass 'sort=False'.
+
+To retain the current behavior and silence the warning, pass 'sort=True'.
+"""
+)
+
+
+__all__ = [
+    "Index",
+    "MultiIndex",
+    "CategoricalIndex",
+    "IntervalIndex",
+    "RangeIndex",
+    "InvalidIndexError",
+    "TimedeltaIndex",
+    "PeriodIndex",
+    "DatetimeIndex",
+    "_new_Index",
+    "NaT",
+    "ensure_index",
+    "ensure_index_from_sequences",
+    "get_objs_combined_axis",
+    "union_indexes",
+    "get_unanimous_names",
+    "all_indexes_same",
+    "default_index",
+    "safe_sort_index",
+]
+
+
+def get_objs_combined_axis(
+    objs,
+    intersect: bool = False,
+    axis: Axis = 0,
+    sort: bool = True,
+    copy: bool = False,
+) -> Index:
+    """
+    Extract combined index: return intersection or union (depending on the
+    value of "intersect") of indexes on given axis, or None if all objects
+    lack indexes (e.g. they are numpy arrays).
+
+    Parameters
+    ----------
+    objs : list
+        Series or DataFrame objects, may be mix of the two.
+    intersect : bool, default False
+        If True, calculate the intersection between indexes. Otherwise,
+        calculate the union.
+    axis : {0 or 'index', 1 or 'outer'}, default 0
+        The axis to extract indexes from.
+    sort : bool, default True
+        Whether the result index should come out sorted or not.
+    copy : bool, default False
+        If True, return a copy of the combined index.
+
+    Returns
+    -------
+    Index
+    """
+    obs_idxes = [obj._get_axis(axis) for obj in objs]
+    return _get_combined_index(obs_idxes, intersect=intersect, sort=sort, copy=copy)
+
+
+def _get_distinct_objs(objs: list[Index]) -> list[Index]:
+    """
+    Return a list with distinct elements of "objs" (different ids).
+    Preserves order.
+    """
+    ids: set[int] = set()
+    res = []
+    for obj in objs:
+        if id(obj) not in ids:
+            ids.add(id(obj))
+            res.append(obj)
+    return res
+
+
+def _get_combined_index(
+    indexes: list[Index],
+    intersect: bool = False,
+    sort: bool = False,
+    copy: bool = False,
+) -> Index:
+    """
+    Return the union or intersection of indexes.
+
+    Parameters
+    ----------
+    indexes : list of Index or list objects
+        When intersect=True, do not accept list of lists.
+    intersect : bool, default False
+        If True, calculate the intersection between indexes. Otherwise,
+        calculate the union.
+    sort : bool, default False
+        Whether the result index should come out sorted or not.
+    copy : bool, default False
+        If True, return a copy of the combined index.
+
+    Returns
+    -------
+    Index
+    """
+    # TODO: handle index names!
+    indexes = _get_distinct_objs(indexes)
+    if len(indexes) == 0:
+        index = Index([])
+    elif len(indexes) == 1:
+        index = indexes[0]
+    elif intersect:
+        index = indexes[0]
+        for other in indexes[1:]:
+            index = index.intersection(other)
+    else:
+        index = union_indexes(indexes, sort=False)
+        index = ensure_index(index)
+
+    if sort:
+        index = safe_sort_index(index)
+    # GH 29879
+    if copy:
+        index = index.copy()
+
+    return index
+
+
+def safe_sort_index(index: Index) -> Index:
+    """
+    Returns the sorted index
+
+    We keep the dtypes and the name attributes.
+
+    Parameters
+    ----------
+    index : an Index
+
+    Returns
+    -------
+    Index
+    """
+    if index.is_monotonic_increasing:
+        return index
+
+    try:
+        array_sorted = safe_sort(index)
+    except TypeError:
+        pass
+    else:
+        if isinstance(array_sorted, Index):
+            return array_sorted
+
+        array_sorted = cast(np.ndarray, array_sorted)
+        if isinstance(index, MultiIndex):
+            index = MultiIndex.from_tuples(array_sorted, names=index.names)
+        else:
+            index = Index(array_sorted, name=index.name, dtype=index.dtype)
+
+    return index
+
+
+def union_indexes(indexes, sort: bool | None = True) -> Index:
+    """
+    Return the union of indexes.
+
+    The behavior of sort and names is not consistent.
+
+    Parameters
+    ----------
+    indexes : list of Index or list objects
+    sort : bool, default True
+        Whether the result index should come out sorted or not.
+
+    Returns
+    -------
+    Index
+    """
+    if len(indexes) == 0:
+        raise AssertionError("Must have at least 1 Index to union")
+    if len(indexes) == 1:
+        result = indexes[0]
+        if isinstance(result, list):
+            if not sort:
+                result = Index(result)
+            else:
+                result = Index(sorted(result))
+        return result
+
+    indexes, kind = _sanitize_and_check(indexes)
+
+    def _unique_indices(inds, dtype) -> Index:
+        """
+        Concatenate indices and remove duplicates.
+
+        Parameters
+        ----------
+        inds : list of Index or list objects
+        dtype : dtype to set for the resulting Index
+
+        Returns
+        -------
+        Index
+        """
+        if all(isinstance(ind, Index) for ind in inds):
+            inds = [ind.astype(dtype, copy=False) for ind in inds]
+            result = inds[0].unique()
+            other = inds[1].append(inds[2:])
+            diff = other[result.get_indexer_for(other) == -1]
+            if len(diff):
+                result = result.append(diff.unique())
+            if sort:
+                result = result.sort_values()
+            return result
+
+        def conv(i):
+            if isinstance(i, Index):
+                i = i.tolist()
+            return i
+
+        return Index(
+            lib.fast_unique_multiple_list([conv(i) for i in inds], sort=sort),
+            dtype=dtype,
+        )
+
+    def _find_common_index_dtype(inds):
+        """
+        Finds a common type for the indexes to pass through to resulting index.
+
+        Parameters
+        ----------
+        inds: list of Index or list objects
+
+        Returns
+        -------
+        The common type or None if no indexes were given
+        """
+        dtypes = [idx.dtype for idx in indexes if isinstance(idx, Index)]
+        if dtypes:
+            dtype = find_common_type(dtypes)
+        else:
+            dtype = None
+
+        return dtype
+
+    if kind == "special":
+        result = indexes[0]
+
+        dtis = [x for x in indexes if isinstance(x, DatetimeIndex)]
+        dti_tzs = [x for x in dtis if x.tz is not None]
+        if len(dti_tzs) not in [0, len(dtis)]:
+            # TODO: this behavior is not tested (so may not be desired),
+            #  but is kept in order to keep behavior the same when
+            #  deprecating union_many
+            # test_frame_from_dict_with_mixed_indexes
+            raise TypeError("Cannot join tz-naive with tz-aware DatetimeIndex")
+
+        if len(dtis) == len(indexes):
+            sort = True
+            result = indexes[0]
+
+        elif len(dtis) > 1:
+            # If we have mixed timezones, our casting behavior may depend on
+            #  the order of indexes, which we don't want.
+            sort = False
+
+            # TODO: what about Categorical[dt64]?
+            # test_frame_from_dict_with_mixed_indexes
+            indexes = [x.astype(object, copy=False) for x in indexes]
+            result = indexes[0]
+
+        for other in indexes[1:]:
+            result = result.union(other, sort=None if sort else False)
+        return result
+
+    elif kind == "array":
+        dtype = _find_common_index_dtype(indexes)
+        index = indexes[0]
+        if not all(index.equals(other) for other in indexes[1:]):
+            index = _unique_indices(indexes, dtype)
+
+        name = get_unanimous_names(*indexes)[0]
+        if name != index.name:
+            index = index.rename(name)
+        return index
+    else:  # kind='list'
+        dtype = _find_common_index_dtype(indexes)
+        return _unique_indices(indexes, dtype)
+
+
+def _sanitize_and_check(indexes):
+    """
+    Verify the type of indexes and convert lists to Index.
+
+    Cases:
+
+    - [list, list, ...]: Return ([list, list, ...], 'list')
+    - [list, Index, ...]: Return _sanitize_and_check([Index, Index, ...])
+        Lists are sorted and converted to Index.
+    - [Index, Index, ...]: Return ([Index, Index, ...], TYPE)
+        TYPE = 'special' if at least one special type, 'array' otherwise.
+
+    Parameters
+    ----------
+    indexes : list of Index or list objects
+
+    Returns
+    -------
+    sanitized_indexes : list of Index or list objects
+    type : {'list', 'array', 'special'}
+    """
+    kinds = list({type(index) for index in indexes})
+
+    if list in kinds:
+        if len(kinds) > 1:
+            indexes = [
+                Index(list(x)) if not isinstance(x, Index) else x for x in indexes
+            ]
+            kinds.remove(list)
+        else:
+            return indexes, "list"
+
+    if len(kinds) > 1 or Index not in kinds:
+        return indexes, "special"
+    else:
+        return indexes, "array"
+
+
+def all_indexes_same(indexes) -> bool:
+    """
+    Determine if all indexes contain the same elements.
+
+    Parameters
+    ----------
+    indexes : iterable of Index objects
+
+    Returns
+    -------
+    bool
+        True if all indexes contain the same elements, False otherwise.
+    """
+    itr = iter(indexes)
+    first = next(itr)
+    return all(first.equals(index) for index in itr)
+
+
+def default_index(n: int) -> RangeIndex:
+    rng = range(n)
+    return RangeIndex._simple_new(rng, name=None)

lib/python3.13/site-packages/pandas/core/indexes/category.py

@@ -0,0 +1,513 @@
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Literal,
+    cast,
+)
+
+import numpy as np
+
+from pandas._libs import index as libindex
+from pandas.util._decorators import (
+    cache_readonly,
+    doc,
+)
+
+from pandas.core.dtypes.common import is_scalar
+from pandas.core.dtypes.concat import concat_compat
+from pandas.core.dtypes.dtypes import CategoricalDtype
+from pandas.core.dtypes.missing import (
+    is_valid_na_for_dtype,
+    isna,
+)
+
+from pandas.core.arrays.categorical import (
+    Categorical,
+    contains,
+)
+from pandas.core.construction import extract_array
+from pandas.core.indexes.base import (
+    Index,
+    maybe_extract_name,
+)
+from pandas.core.indexes.extension import (
+    NDArrayBackedExtensionIndex,
+    inherit_names,
+)
+
+if TYPE_CHECKING:
+    from collections.abc import Hashable
+
+    from pandas._typing import (
+        Dtype,
+        DtypeObj,
+        Self,
+        npt,
+    )
+
+
+@inherit_names(
+    [
+        "argsort",
+        "tolist",
+        "codes",
+        "categories",
+        "ordered",
+        "_reverse_indexer",
+        "searchsorted",
+        "min",
+        "max",
+    ],
+    Categorical,
+)
+@inherit_names(
+    [
+        "rename_categories",
+        "reorder_categories",
+        "add_categories",
+        "remove_categories",
+        "remove_unused_categories",
+        "set_categories",
+        "as_ordered",
+        "as_unordered",
+    ],
+    Categorical,
+    wrap=True,
+)
+class CategoricalIndex(NDArrayBackedExtensionIndex):
+    """
+    Index based on an underlying :class:`Categorical`.
+
+    CategoricalIndex, like Categorical, can only take on a limited,
+    and usually fixed, number of possible values (`categories`). Also,
+    like Categorical, it might have an order, but numerical operations
+    (additions, divisions, ...) are not possible.
+
+    Parameters
+    ----------
+    data : array-like (1-dimensional)
+        The values of the categorical. If `categories` are given, values not in
+        `categories` will be replaced with NaN.
+    categories : index-like, optional
+        The categories for the categorical. Items need to be unique.
+        If the categories are not given here (and also not in `dtype`), they
+        will be inferred from the `data`.
+    ordered : bool, optional
+        Whether or not this categorical is treated as an ordered
+        categorical. If not given here or in `dtype`, the resulting
+        categorical will be unordered.
+    dtype : CategoricalDtype or "category", optional
+        If :class:`CategoricalDtype`, cannot be used together with
+        `categories` or `ordered`.
+    copy : bool, default False
+        Make a copy of input ndarray.
+    name : object, optional
+        Name to be stored in the index.
+
+    Attributes
+    ----------
+    codes
+    categories
+    ordered
+
+    Methods
+    -------
+    rename_categories
+    reorder_categories
+    add_categories
+    remove_categories
+    remove_unused_categories
+    set_categories
+    as_ordered
+    as_unordered
+    map
+
+    Raises
+    ------
+    ValueError
+        If the categories do not validate.
+    TypeError
+        If an explicit ``ordered=True`` is given but no `categories` and the
+        `values` are not sortable.
+
+    See Also
+    --------
+    Index : The base pandas Index type.
+    Categorical : A categorical array.
+    CategoricalDtype : Type for categorical data.
+
+    Notes
+    -----
+    See the `user guide
+    <https://pandas.pydata.org/pandas-docs/stable/user_guide/advanced.html#categoricalindex>`__
+    for more.
+
+    Examples
+    --------
+    >>> pd.CategoricalIndex(["a", "b", "c", "a", "b", "c"])
+    CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'],
+                     categories=['a', 'b', 'c'], ordered=False, dtype='category')
+
+    ``CategoricalIndex`` can also be instantiated from a ``Categorical``:
+
+    >>> c = pd.Categorical(["a", "b", "c", "a", "b", "c"])
+    >>> pd.CategoricalIndex(c)
+    CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'],
+                     categories=['a', 'b', 'c'], ordered=False, dtype='category')
+
+    Ordered ``CategoricalIndex`` can have a min and max value.
+
+    >>> ci = pd.CategoricalIndex(
+    ...     ["a", "b", "c", "a", "b", "c"], ordered=True, categories=["c", "b", "a"]
+    ... )
+    >>> ci
+    CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'],
+                     categories=['c', 'b', 'a'], ordered=True, dtype='category')
+    >>> ci.min()
+    'c'
+    """
+
+    _typ = "categoricalindex"
+    _data_cls = Categorical
+
+    @property
+    def _can_hold_strings(self):
+        return self.categories._can_hold_strings
+
+    @cache_readonly
+    def _should_fallback_to_positional(self) -> bool:
+        return self.categories._should_fallback_to_positional
+
+    codes: np.ndarray
+    categories: Index
+    ordered: bool | None
+    _data: Categorical
+    _values: Categorical
+
+    @property
+    def _engine_type(self) -> type[libindex.IndexEngine]:
+        # self.codes can have dtype int8, int16, int32 or int64, so we need
+        # to return the corresponding engine type (libindex.Int8Engine, etc.).
+        return {
+            np.int8: libindex.Int8Engine,
+            np.int16: libindex.Int16Engine,
+            np.int32: libindex.Int32Engine,
+            np.int64: libindex.Int64Engine,
+        }[self.codes.dtype.type]
+
+    # --------------------------------------------------------------------
+    # Constructors
+
+    def __new__(
+        cls,
+        data=None,
+        categories=None,
+        ordered=None,
+        dtype: Dtype | None = None,
+        copy: bool = False,
+        name: Hashable | None = None,
+    ) -> Self:
+        name = maybe_extract_name(name, data, cls)
+
+        if is_scalar(data):
+            # GH#38944 include None here, which pre-2.0 subbed in []
+            cls._raise_scalar_data_error(data)
+
+        data = Categorical(
+            data, categories=categories, ordered=ordered, dtype=dtype, copy=copy
+        )
+
+        return cls._simple_new(data, name=name)
+
+    # --------------------------------------------------------------------
+
+    def _is_dtype_compat(self, other: Index) -> Categorical:
+        """
+        *this is an internal non-public method*
+
+        provide a comparison between the dtype of self and other (coercing if
+        needed)
+
+        Parameters
+        ----------
+        other : Index
+
+        Returns
+        -------
+        Categorical
+
+        Raises
+        ------
+        TypeError if the dtypes are not compatible
+        """
+        if isinstance(other.dtype, CategoricalDtype):
+            cat = extract_array(other)
+            cat = cast(Categorical, cat)
+            if not cat._categories_match_up_to_permutation(self._values):
+                raise TypeError(
+                    "categories must match existing categories when appending"
+                )
+
+        elif other._is_multi:
+            # preempt raising NotImplementedError in isna call
+            raise TypeError("MultiIndex is not dtype-compatible with CategoricalIndex")
+        else:
+            values = other
+
+            cat = Categorical(other, dtype=self.dtype)
+            other = CategoricalIndex(cat)
+            if not other.isin(values).all():
+                raise TypeError(
+                    "cannot append a non-category item to a CategoricalIndex"
+                )
+            cat = other._values
+
+            if not ((cat == values) | (isna(cat) & isna(values))).all():
+                # GH#37667 see test_equals_non_category
+                raise TypeError(
+                    "categories must match existing categories when appending"
+                )
+
+        return cat
+
+    def equals(self, other: object) -> bool:
+        """
+        Determine if two CategoricalIndex objects contain the same elements.
+
+        Returns
+        -------
+        bool
+            ``True`` if two :class:`pandas.CategoricalIndex` objects have equal
+            elements, ``False`` otherwise.
+
+        Examples
+        --------
+        >>> ci = pd.CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'])
+        >>> ci2 = pd.CategoricalIndex(pd.Categorical(['a', 'b', 'c', 'a', 'b', 'c']))
+        >>> ci.equals(ci2)
+        True
+
+        The order of elements matters.
+
+        >>> ci3 = pd.CategoricalIndex(['c', 'b', 'a', 'a', 'b', 'c'])
+        >>> ci.equals(ci3)
+        False
+
+        The orderedness also matters.
+
+        >>> ci4 = ci.as_ordered()
+        >>> ci.equals(ci4)
+        False
+
+        The categories matter, but the order of the categories matters only when
+        ``ordered=True``.
+
+        >>> ci5 = ci.set_categories(['a', 'b', 'c', 'd'])
+        >>> ci.equals(ci5)
+        False
+
+        >>> ci6 = ci.set_categories(['b', 'c', 'a'])
+        >>> ci.equals(ci6)
+        True
+        >>> ci_ordered = pd.CategoricalIndex(['a', 'b', 'c', 'a', 'b', 'c'],
+        ...                                  ordered=True)
+        >>> ci2_ordered = ci_ordered.set_categories(['b', 'c', 'a'])
+        >>> ci_ordered.equals(ci2_ordered)
+        False
+        """
+        if self.is_(other):
+            return True
+
+        if not isinstance(other, Index):
+            return False
+
+        try:
+            other = self._is_dtype_compat(other)
+        except (TypeError, ValueError):
+            return False
+
+        return self._data.equals(other)
+
+    # --------------------------------------------------------------------
+    # Rendering Methods
+
+    @property
+    def _formatter_func(self):
+        return self.categories._formatter_func
+
+    def _format_attrs(self):
+        """
+        Return a list of tuples of the (attr,formatted_value)
+        """
+        attrs: list[tuple[str, str | int | bool | None]]
+
+        attrs = [
+            (
+                "categories",
+                f"[{', '.join(self._data._repr_categories())}]",
+            ),
+            ("ordered", self.ordered),
+        ]
+        extra = super()._format_attrs()
+        return attrs + extra
+
+    # --------------------------------------------------------------------
+
+    @property
+    def inferred_type(self) -> str:
+        return "categorical"
+
+    @doc(Index.__contains__)
+    def __contains__(self, key: Any) -> bool:
+        # if key is a NaN, check if any NaN is in self.
+        if is_valid_na_for_dtype(key, self.categories.dtype):
+            return self.hasnans
+
+        return contains(self, key, container=self._engine)
+
+    def reindex(
+        self, target, method=None, level=None, limit: int | None = None, tolerance=None
+    ) -> tuple[Index, npt.NDArray[np.intp] | None]:
+        """
+        Create index with target's values (move/add/delete values as necessary)
+
+        Returns
+        -------
+        new_index : pd.Index
+            Resulting index
+        indexer : np.ndarray[np.intp] or None
+            Indices of output values in original index
+
+        """
+        if method is not None:
+            raise NotImplementedError(
+                "argument method is not implemented for CategoricalIndex.reindex"
+            )
+        if level is not None:
+            raise NotImplementedError(
+                "argument level is not implemented for CategoricalIndex.reindex"
+            )
+        if limit is not None:
+            raise NotImplementedError(
+                "argument limit is not implemented for CategoricalIndex.reindex"
+            )
+        return super().reindex(target)
+
+    # --------------------------------------------------------------------
+    # Indexing Methods
+
+    def _maybe_cast_indexer(self, key) -> int:
+        # GH#41933: we have to do this instead of self._data._validate_scalar
+        #  because this will correctly get partial-indexing on Interval categories
+        try:
+            return self._data._unbox_scalar(key)
+        except KeyError:
+            if is_valid_na_for_dtype(key, self.categories.dtype):
+                return -1
+            raise
+
+    def _maybe_cast_listlike_indexer(self, values) -> CategoricalIndex:
+        if isinstance(values, CategoricalIndex):
+            values = values._data
+        if isinstance(values, Categorical):
+            # Indexing on codes is more efficient if categories are the same,
+            #  so we can apply some optimizations based on the degree of
+            #  dtype-matching.
+            cat = self._data._encode_with_my_categories(values)
+            codes = cat._codes
+        else:
+            codes = self.categories.get_indexer(values)
+            codes = codes.astype(self.codes.dtype, copy=False)
+            cat = self._data._from_backing_data(codes)
+        return type(self)._simple_new(cat)
+
+    # --------------------------------------------------------------------
+
+    def _is_comparable_dtype(self, dtype: DtypeObj) -> bool:
+        return self.categories._is_comparable_dtype(dtype)
+
+    def map(self, mapper, na_action: Literal["ignore"] | None = None):
+        """
+        Map values using input an input mapping or function.
+
+        Maps the values (their categories, not the codes) of the index to new
+        categories. If the mapping correspondence is one-to-one the result is a
+        :class:`~pandas.CategoricalIndex` which has the same order property as
+        the original, otherwise an :class:`~pandas.Index` is returned.
+
+        If a `dict` or :class:`~pandas.Series` is used any unmapped category is
+        mapped to `NaN`. Note that if this happens an :class:`~pandas.Index`
+        will be returned.
+
+        Parameters
+        ----------
+        mapper : function, dict, or Series
+            Mapping correspondence.
+
+        Returns
+        -------
+        pandas.CategoricalIndex or pandas.Index
+            Mapped index.
+
+        See Also
+        --------
+        Index.map : Apply a mapping correspondence on an
+            :class:`~pandas.Index`.
+        Series.map : Apply a mapping correspondence on a
+            :class:`~pandas.Series`.
+        Series.apply : Apply more complex functions on a
+            :class:`~pandas.Series`.
+
+        Examples
+        --------
+        >>> idx = pd.CategoricalIndex(['a', 'b', 'c'])
+        >>> idx
+        CategoricalIndex(['a', 'b', 'c'], categories=['a', 'b', 'c'],
+                          ordered=False, dtype='category')
+        >>> idx.map(lambda x: x.upper())
+        CategoricalIndex(['A', 'B', 'C'], categories=['A', 'B', 'C'],
+                         ordered=False, dtype='category')
+        >>> idx.map({'a': 'first', 'b': 'second', 'c': 'third'})
+        CategoricalIndex(['first', 'second', 'third'], categories=['first',
+                         'second', 'third'], ordered=False, dtype='category')
+
+        If the mapping is one-to-one the ordering of the categories is
+        preserved:
+
+        >>> idx = pd.CategoricalIndex(['a', 'b', 'c'], ordered=True)
+        >>> idx
+        CategoricalIndex(['a', 'b', 'c'], categories=['a', 'b', 'c'],
+                         ordered=True, dtype='category')
+        >>> idx.map({'a': 3, 'b': 2, 'c': 1})
+        CategoricalIndex([3, 2, 1], categories=[3, 2, 1], ordered=True,
+                         dtype='category')
+
+        If the mapping is not one-to-one an :class:`~pandas.Index` is returned:
+
+        >>> idx.map({'a': 'first', 'b': 'second', 'c': 'first'})
+        Index(['first', 'second', 'first'], dtype='object')
+
+        If a `dict` is used, all unmapped categories are mapped to `NaN` and
+        the result is an :class:`~pandas.Index`:
+
+        >>> idx.map({'a': 'first', 'b': 'second'})
+        Index(['first', 'second', nan], dtype='object')
+        """
+        mapped = self._values.map(mapper, na_action=na_action)
+        return Index(mapped, name=self.name)
+
+    def _concat(self, to_concat: list[Index], name: Hashable) -> Index:
+        # if calling index is category, don't check dtype of others
+        try:
+            cat = Categorical._concat_same_type(
+                [self._is_dtype_compat(c) for c in to_concat]
+            )
+        except TypeError:
+            # not all to_concat elements are among our categories (or NA)
+
+            res = concat_compat([x._values for x in to_concat])
+            return Index(res, name=name)
+        else:
+            return type(self)._simple_new(cat, name=name)

lib/python3.13/site-packages/pandas/core/indexes/datetimelike.py

@@ -0,0 +1,843 @@
+"""
+Base and utility classes for tseries type pandas objects.
+"""
+from __future__ import annotations
+
+from abc import (
+    ABC,
+    abstractmethod,
+)
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Callable,
+    cast,
+    final,
+)
+import warnings
+
+import numpy as np
+
+from pandas._config import using_copy_on_write
+
+from pandas._libs import (
+    NaT,
+    Timedelta,
+    lib,
+)
+from pandas._libs.tslibs import (
+    BaseOffset,
+    Resolution,
+    Tick,
+    parsing,
+    to_offset,
+)
+from pandas._libs.tslibs.dtypes import freq_to_period_freqstr
+from pandas.compat.numpy import function as nv
+from pandas.errors import (
+    InvalidIndexError,
+    NullFrequencyError,
+)
+from pandas.util._decorators import (
+    Appender,
+    cache_readonly,
+    doc,
+)
+from pandas.util._exceptions import find_stack_level
+
+from pandas.core.dtypes.common import (
+    is_integer,
+    is_list_like,
+)
+from pandas.core.dtypes.concat import concat_compat
+from pandas.core.dtypes.dtypes import CategoricalDtype
+
+from pandas.core.arrays import (
+    DatetimeArray,
+    ExtensionArray,
+    PeriodArray,
+    TimedeltaArray,
+)
+from pandas.core.arrays.datetimelike import DatetimeLikeArrayMixin
+import pandas.core.common as com
+import pandas.core.indexes.base as ibase
+from pandas.core.indexes.base import (
+    Index,
+    _index_shared_docs,
+)
+from pandas.core.indexes.extension import NDArrayBackedExtensionIndex
+from pandas.core.indexes.range import RangeIndex
+from pandas.core.tools.timedeltas import to_timedelta
+
+if TYPE_CHECKING:
+    from collections.abc import Sequence
+    from datetime import datetime
+
+    from pandas._typing import (
+        Axis,
+        Self,
+        npt,
+    )
+
+    from pandas import CategoricalIndex
+
+_index_doc_kwargs = dict(ibase._index_doc_kwargs)
+
+
+class DatetimeIndexOpsMixin(NDArrayBackedExtensionIndex, ABC):
+    """
+    Common ops mixin to support a unified interface datetimelike Index.
+    """
+
+    _can_hold_strings = False
+    _data: DatetimeArray | TimedeltaArray | PeriodArray
+
+    @doc(DatetimeLikeArrayMixin.mean)
+    def mean(self, *, skipna: bool = True, axis: int | None = 0):
+        return self._data.mean(skipna=skipna, axis=axis)
+
+    @property
+    def freq(self) -> BaseOffset | None:
+        return self._data.freq
+
+    @freq.setter
+    def freq(self, value) -> None:
+        # error: Property "freq" defined in "PeriodArray" is read-only  [misc]
+        self._data.freq = value  # type: ignore[misc]
+
+    @property
+    def asi8(self) -> npt.NDArray[np.int64]:
+        return self._data.asi8
+
+    @property
+    @doc(DatetimeLikeArrayMixin.freqstr)
+    def freqstr(self) -> str:
+        from pandas import PeriodIndex
+
+        if self._data.freqstr is not None and isinstance(
+            self._data, (PeriodArray, PeriodIndex)
+        ):
+            freq = freq_to_period_freqstr(self._data.freq.n, self._data.freq.name)
+            return freq
+        else:
+            return self._data.freqstr  # type: ignore[return-value]
+
+    @cache_readonly
+    @abstractmethod
+    def _resolution_obj(self) -> Resolution:
+        ...
+
+    @cache_readonly
+    @doc(DatetimeLikeArrayMixin.resolution)
+    def resolution(self) -> str:
+        return self._data.resolution
+
+    # ------------------------------------------------------------------------
+
+    @cache_readonly
+    def hasnans(self) -> bool:
+        return self._data._hasna
+
+    def equals(self, other: Any) -> bool:
+        """
+        Determines if two Index objects contain the same elements.
+        """
+        if self.is_(other):
+            return True
+
+        if not isinstance(other, Index):
+            return False
+        elif other.dtype.kind in "iufc":
+            return False
+        elif not isinstance(other, type(self)):
+            should_try = False
+            inferable = self._data._infer_matches
+            if other.dtype == object:
+                should_try = other.inferred_type in inferable
+            elif isinstance(other.dtype, CategoricalDtype):
+                other = cast("CategoricalIndex", other)
+                should_try = other.categories.inferred_type in inferable
+
+            if should_try:
+                try:
+                    other = type(self)(other)
+                except (ValueError, TypeError, OverflowError):
+                    # e.g.
+                    #  ValueError -> cannot parse str entry, or OutOfBoundsDatetime
+                    #  TypeError  -> trying to convert IntervalIndex to DatetimeIndex
+                    #  OverflowError -> Index([very_large_timedeltas])
+                    return False
+
+        if self.dtype != other.dtype:
+            # have different timezone
+            return False
+
+        return np.array_equal(self.asi8, other.asi8)
+
+    @Appender(Index.__contains__.__doc__)
+    def __contains__(self, key: Any) -> bool:
+        hash(key)
+        try:
+            self.get_loc(key)
+        except (KeyError, TypeError, ValueError, InvalidIndexError):
+            return False
+        return True
+
+    def _convert_tolerance(self, tolerance, target):
+        tolerance = np.asarray(to_timedelta(tolerance).to_numpy())
+        return super()._convert_tolerance(tolerance, target)
+
+    # --------------------------------------------------------------------
+    # Rendering Methods
+    _default_na_rep = "NaT"
+
+    def format(
+        self,
+        name: bool = False,
+        formatter: Callable | None = None,
+        na_rep: str = "NaT",
+        date_format: str | None = None,
+    ) -> list[str]:
+        """
+        Render a string representation of the Index.
+        """
+        warnings.warn(
+            # GH#55413
+            f"{type(self).__name__}.format is deprecated and will be removed "
+            "in a future version. Convert using index.astype(str) or "
+            "index.map(formatter) instead.",
+            FutureWarning,
+            stacklevel=find_stack_level(),
+        )
+        header = []
+        if name:
+            header.append(
+                ibase.pprint_thing(self.name, escape_chars=("\t", "\r", "\n"))
+                if self.name is not None
+                else ""
+            )
+
+        if formatter is not None:
+            return header + list(self.map(formatter))
+
+        return self._format_with_header(
+            header=header, na_rep=na_rep, date_format=date_format
+        )
+
+    def _format_with_header(
+        self, *, header: list[str], na_rep: str, date_format: str | None = None
+    ) -> list[str]:
+        # TODO: not reached in tests 2023-10-11
+        # matches base class except for whitespace padding and date_format
+        return header + list(
+            self._get_values_for_csv(na_rep=na_rep, date_format=date_format)
+        )
+
+    @property
+    def _formatter_func(self):
+        return self._data._formatter()
+
+    def _format_attrs(self):
+        """
+        Return a list of tuples of the (attr,formatted_value).
+        """
+        attrs = super()._format_attrs()
+        for attrib in self._attributes:
+            # iterating over _attributes prevents us from doing this for PeriodIndex
+            if attrib == "freq":
+                freq = self.freqstr
+                if freq is not None:
+                    freq = repr(freq)  # e.g. D -> 'D'
+                attrs.append(("freq", freq))
+        return attrs
+
+    @Appender(Index._summary.__doc__)
+    def _summary(self, name=None) -> str:
+        result = super()._summary(name=name)
+        if self.freq:
+            result += f"\nFreq: {self.freqstr}"
+
+        return result
+
+    # --------------------------------------------------------------------
+    # Indexing Methods
+
+    @final
+    def _can_partial_date_slice(self, reso: Resolution) -> bool:
+        # e.g. test_getitem_setitem_periodindex
+        # History of conversation GH#3452, GH#3931, GH#2369, GH#14826
+        return reso > self._resolution_obj
+        # NB: for DTI/PI, not TDI
+
+    def _parsed_string_to_bounds(self, reso: Resolution, parsed):
+        raise NotImplementedError
+
+    def _parse_with_reso(self, label: str):
+        # overridden by TimedeltaIndex
+        try:
+            if self.freq is None or hasattr(self.freq, "rule_code"):
+                freq = self.freq
+        except NotImplementedError:
+            freq = getattr(self, "freqstr", getattr(self, "inferred_freq", None))
+
+        freqstr: str | None
+        if freq is not None and not isinstance(freq, str):
+            freqstr = freq.rule_code
+        else:
+            freqstr = freq
+
+        if isinstance(label, np.str_):
+            # GH#45580
+            label = str(label)
+
+        parsed, reso_str = parsing.parse_datetime_string_with_reso(label, freqstr)
+        reso = Resolution.from_attrname(reso_str)
+        return parsed, reso
+
+    def _get_string_slice(self, key: str):
+        # overridden by TimedeltaIndex
+        parsed, reso = self._parse_with_reso(key)
+        try:
+            return self._partial_date_slice(reso, parsed)
+        except KeyError as err:
+            raise KeyError(key) from err
+
+    @final
+    def _partial_date_slice(
+        self,
+        reso: Resolution,
+        parsed: datetime,
+    ) -> slice | npt.NDArray[np.intp]:
+        """
+        Parameters
+        ----------
+        reso : Resolution
+        parsed : datetime
+
+        Returns
+        -------
+        slice or ndarray[intp]
+        """
+        if not self._can_partial_date_slice(reso):
+            raise ValueError
+
+        t1, t2 = self._parsed_string_to_bounds(reso, parsed)
+        vals = self._data._ndarray
+        unbox = self._data._unbox
+
+        if self.is_monotonic_increasing:
+            if len(self) and (
+                (t1 < self[0] and t2 < self[0]) or (t1 > self[-1] and t2 > self[-1])
+            ):
+                # we are out of range
+                raise KeyError
+
+            # TODO: does this depend on being monotonic _increasing_?
+
+            # a monotonic (sorted) series can be sliced
+            left = vals.searchsorted(unbox(t1), side="left")
+            right = vals.searchsorted(unbox(t2), side="right")
+            return slice(left, right)
+
+        else:
+            lhs_mask = vals >= unbox(t1)
+            rhs_mask = vals <= unbox(t2)
+
+            # try to find the dates
+            return (lhs_mask & rhs_mask).nonzero()[0]
+
+    def _maybe_cast_slice_bound(self, label, side: str):
+        """
+        If label is a string, cast it to scalar type according to resolution.
+
+        Parameters
+        ----------
+        label : object
+        side : {'left', 'right'}
+
+        Returns
+        -------
+        label : object
+
+        Notes
+        -----
+        Value of `side` parameter should be validated in caller.
+        """
+        if isinstance(label, str):
+            try:
+                parsed, reso = self._parse_with_reso(label)
+            except ValueError as err:
+                # DTI -> parsing.DateParseError
+                # TDI -> 'unit abbreviation w/o a number'
+                # PI -> string cannot be parsed as datetime-like
+                self._raise_invalid_indexer("slice", label, err)
+
+            lower, upper = self._parsed_string_to_bounds(reso, parsed)
+            return lower if side == "left" else upper
+        elif not isinstance(label, self._data._recognized_scalars):
+            self._raise_invalid_indexer("slice", label)
+
+        return label
+
+    # --------------------------------------------------------------------
+    # Arithmetic Methods
+
+    def shift(self, periods: int = 1, freq=None) -> Self:
+        """
+        Shift index by desired number of time frequency increments.
+
+        This method is for shifting the values of datetime-like indexes
+        by a specified time increment a given number of times.
+
+        Parameters
+        ----------
+        periods : int, default 1
+            Number of periods (or increments) to shift by,
+            can be positive or negative.
+        freq : pandas.DateOffset, pandas.Timedelta or string, optional
+            Frequency increment to shift by.
+            If None, the index is shifted by its own `freq` attribute.
+            Offset aliases are valid strings, e.g., 'D', 'W', 'M' etc.
+
+        Returns
+        -------
+        pandas.DatetimeIndex
+            Shifted index.
+
+        See Also
+        --------
+        Index.shift : Shift values of Index.
+        PeriodIndex.shift : Shift values of PeriodIndex.
+        """
+        raise NotImplementedError
+
+    # --------------------------------------------------------------------
+
+    @doc(Index._maybe_cast_listlike_indexer)
+    def _maybe_cast_listlike_indexer(self, keyarr):
+        try:
+            res = self._data._validate_listlike(keyarr, allow_object=True)
+        except (ValueError, TypeError):
+            if not isinstance(keyarr, ExtensionArray):
+                # e.g. we don't want to cast DTA to ndarray[object]
+                res = com.asarray_tuplesafe(keyarr)
+                # TODO: com.asarray_tuplesafe shouldn't cast e.g. DatetimeArray
+            else:
+                res = keyarr
+        return Index(res, dtype=res.dtype)
+
+
+class DatetimeTimedeltaMixin(DatetimeIndexOpsMixin, ABC):
+    """
+    Mixin class for methods shared by DatetimeIndex and TimedeltaIndex,
+    but not PeriodIndex
+    """
+
+    _data: DatetimeArray | TimedeltaArray
+    _comparables = ["name", "freq"]
+    _attributes = ["name", "freq"]
+
+    # Compat for frequency inference, see GH#23789
+    _is_monotonic_increasing = Index.is_monotonic_increasing
+    _is_monotonic_decreasing = Index.is_monotonic_decreasing
+    _is_unique = Index.is_unique
+
+    @property
+    def unit(self) -> str:
+        return self._data.unit
+
+    def as_unit(self, unit: str) -> Self:
+        """
+        Convert to a dtype with the given unit resolution.
+
+        Parameters
+        ----------
+        unit : {'s', 'ms', 'us', 'ns'}
+
+        Returns
+        -------
+        same type as self
+
+        Examples
+        --------
+        For :class:`pandas.DatetimeIndex`:
+
+        >>> idx = pd.DatetimeIndex(['2020-01-02 01:02:03.004005006'])
+        >>> idx
+        DatetimeIndex(['2020-01-02 01:02:03.004005006'],
+                      dtype='datetime64[ns]', freq=None)
+        >>> idx.as_unit('s')
+        DatetimeIndex(['2020-01-02 01:02:03'], dtype='datetime64[s]', freq=None)
+
+        For :class:`pandas.TimedeltaIndex`:
+
+        >>> tdelta_idx = pd.to_timedelta(['1 day 3 min 2 us 42 ns'])
+        >>> tdelta_idx
+        TimedeltaIndex(['1 days 00:03:00.000002042'],
+                        dtype='timedelta64[ns]', freq=None)
+        >>> tdelta_idx.as_unit('s')
+        TimedeltaIndex(['1 days 00:03:00'], dtype='timedelta64[s]', freq=None)
+        """
+        arr = self._data.as_unit(unit)
+        return type(self)._simple_new(arr, name=self.name)
+
+    def _with_freq(self, freq):
+        arr = self._data._with_freq(freq)
+        return type(self)._simple_new(arr, name=self._name)
+
+    @property
+    def values(self) -> np.ndarray:
+        # NB: For Datetime64TZ this is lossy
+        data = self._data._ndarray
+        if using_copy_on_write():
+            data = data.view()
+            data.flags.writeable = False
+        return data
+
+    @doc(DatetimeIndexOpsMixin.shift)
+    def shift(self, periods: int = 1, freq=None) -> Self:
+        if freq is not None and freq != self.freq:
+            if isinstance(freq, str):
+                freq = to_offset(freq)
+            offset = periods * freq
+            return self + offset
+
+        if periods == 0 or len(self) == 0:
+            # GH#14811 empty case
+            return self.copy()
+
+        if self.freq is None:
+            raise NullFrequencyError("Cannot shift with no freq")
+
+        start = self[0] + periods * self.freq
+        end = self[-1] + periods * self.freq
+
+        # Note: in the DatetimeTZ case, _generate_range will infer the
+        #  appropriate timezone from `start` and `end`, so tz does not need
+        #  to be passed explicitly.
+        result = self._data._generate_range(
+            start=start, end=end, periods=None, freq=self.freq, unit=self.unit
+        )
+        return type(self)._simple_new(result, name=self.name)
+
+    @cache_readonly
+    @doc(DatetimeLikeArrayMixin.inferred_freq)
+    def inferred_freq(self) -> str | None:
+        return self._data.inferred_freq
+
+    # --------------------------------------------------------------------
+    # Set Operation Methods
+
+    @cache_readonly
+    def _as_range_index(self) -> RangeIndex:
+        # Convert our i8 representations to RangeIndex
+        # Caller is responsible for checking isinstance(self.freq, Tick)
+        freq = cast(Tick, self.freq)
+        tick = Timedelta(freq).as_unit("ns")._value
+        rng = range(self[0]._value, self[-1]._value + tick, tick)
+        return RangeIndex(rng)
+
+    def _can_range_setop(self, other) -> bool:
+        return isinstance(self.freq, Tick) and isinstance(other.freq, Tick)
+
+    def _wrap_range_setop(self, other, res_i8) -> Self:
+        new_freq = None
+        if not len(res_i8):
+            # RangeIndex defaults to step=1, which we don't want.
+            new_freq = self.freq
+        elif isinstance(res_i8, RangeIndex):
+            new_freq = to_offset(Timedelta(res_i8.step))
+
+        # TODO(GH#41493): we cannot just do
+        #  type(self._data)(res_i8.values, dtype=self.dtype, freq=new_freq)
+        # because test_setops_preserve_freq fails with _validate_frequency raising.
+        # This raising is incorrect, as 'on_freq' is incorrect. This will
+        # be fixed by GH#41493
+        res_values = res_i8.values.view(self._data._ndarray.dtype)
+        result = type(self._data)._simple_new(
+            # error: Argument "dtype" to "_simple_new" of "DatetimeArray" has
+            # incompatible type "Union[dtype[Any], ExtensionDtype]"; expected
+            # "Union[dtype[datetime64], DatetimeTZDtype]"
+            res_values,
+            dtype=self.dtype,  # type: ignore[arg-type]
+            freq=new_freq,  # type: ignore[arg-type]
+        )
+        return cast("Self", self._wrap_setop_result(other, result))
+
+    def _range_intersect(self, other, sort) -> Self:
+        # Dispatch to RangeIndex intersection logic.
+        left = self._as_range_index
+        right = other._as_range_index
+        res_i8 = left.intersection(right, sort=sort)
+        return self._wrap_range_setop(other, res_i8)
+
+    def _range_union(self, other, sort) -> Self:
+        # Dispatch to RangeIndex union logic.
+        left = self._as_range_index
+        right = other._as_range_index
+        res_i8 = left.union(right, sort=sort)
+        return self._wrap_range_setop(other, res_i8)
+
+    def _intersection(self, other: Index, sort: bool = False) -> Index:
+        """
+        intersection specialized to the case with matching dtypes and both non-empty.
+        """
+        other = cast("DatetimeTimedeltaMixin", other)
+
+        if self._can_range_setop(other):
+            return self._range_intersect(other, sort=sort)
+
+        if not self._can_fast_intersect(other):
+            result = Index._intersection(self, other, sort=sort)
+            # We need to invalidate the freq because Index._intersection
+            #  uses _shallow_copy on a view of self._data, which will preserve
+            #  self.freq if we're not careful.
+            # At this point we should have result.dtype == self.dtype
+            #  and type(result) is type(self._data)
+            result = self._wrap_setop_result(other, result)
+            return result._with_freq(None)._with_freq("infer")
+
+        else:
+            return self._fast_intersect(other, sort)
+
+    def _fast_intersect(self, other, sort):
+        # to make our life easier, "sort" the two ranges
+        if self[0] <= other[0]:
+            left, right = self, other
+        else:
+            left, right = other, self
+
+        # after sorting, the intersection always starts with the right index
+        # and ends with the index of which the last elements is smallest
+        end = min(left[-1], right[-1])
+        start = right[0]
+
+        if end < start:
+            result = self[:0]
+        else:
+            lslice = slice(*left.slice_locs(start, end))
+            result = left._values[lslice]
+
+        return result
+
+    def _can_fast_intersect(self, other: Self) -> bool:
+        # Note: we only get here with len(self) > 0 and len(other) > 0
+        if self.freq is None:
+            return False
+
+        elif other.freq != self.freq:
+            return False
+
+        elif not self.is_monotonic_increasing:
+            # Because freq is not None, we must then be monotonic decreasing
+            return False
+
+        # this along with matching freqs ensure that we "line up",
+        #  so intersection will preserve freq
+        # Note we are assuming away Ticks, as those go through _range_intersect
+        # GH#42104
+        return self.freq.n == 1
+
+    def _can_fast_union(self, other: Self) -> bool:
+        # Assumes that type(self) == type(other), as per the annotation
+        # The ability to fast_union also implies that `freq` should be
+        #  retained on union.
+        freq = self.freq
+
+        if freq is None or freq != other.freq:
+            return False
+
+        if not self.is_monotonic_increasing:
+            # Because freq is not None, we must then be monotonic decreasing
+            # TODO: do union on the reversed indexes?
+            return False
+
+        if len(self) == 0 or len(other) == 0:
+            # only reached via union_many
+            return True
+
+        # to make our life easier, "sort" the two ranges
+        if self[0] <= other[0]:
+            left, right = self, other
+        else:
+            left, right = other, self
+
+        right_start = right[0]
+        left_end = left[-1]
+
+        # Only need to "adjoin", not overlap
+        return (right_start == left_end + freq) or right_start in left
+
+    def _fast_union(self, other: Self, sort=None) -> Self:
+        # Caller is responsible for ensuring self and other are non-empty
+
+        # to make our life easier, "sort" the two ranges
+        if self[0] <= other[0]:
+            left, right = self, other
+        elif sort is False:
+            # TDIs are not in the "correct" order and we don't want
+            #  to sort but want to remove overlaps
+            left, right = self, other
+            left_start = left[0]
+            loc = right.searchsorted(left_start, side="left")
+            right_chunk = right._values[:loc]
+            dates = concat_compat((left._values, right_chunk))
+            result = type(self)._simple_new(dates, name=self.name)
+            return result
+        else:
+            left, right = other, self
+
+        left_end = left[-1]
+        right_end = right[-1]
+
+        # concatenate
+        if left_end < right_end:
+            loc = right.searchsorted(left_end, side="right")
+            right_chunk = right._values[loc:]
+            dates = concat_compat([left._values, right_chunk])
+            # The can_fast_union check ensures that the result.freq
+            #  should match self.freq
+            assert isinstance(dates, type(self._data))
+            # error: Item "ExtensionArray" of "ExtensionArray |
+            # ndarray[Any, Any]" has no attribute "_freq"
+            assert dates._freq == self.freq  # type: ignore[union-attr]
+            result = type(self)._simple_new(dates)
+            return result
+        else:
+            return left
+
+    def _union(self, other, sort):
+        # We are called by `union`, which is responsible for this validation
+        assert isinstance(other, type(self))
+        assert self.dtype == other.dtype
+
+        if self._can_range_setop(other):
+            return self._range_union(other, sort=sort)
+
+        if self._can_fast_union(other):
+            result = self._fast_union(other, sort=sort)
+            # in the case with sort=None, the _can_fast_union check ensures
+            #  that result.freq == self.freq
+            return result
+        else:
+            return super()._union(other, sort)._with_freq("infer")
+
+    # --------------------------------------------------------------------
+    # Join Methods
+
+    def _get_join_freq(self, other):
+        """
+        Get the freq to attach to the result of a join operation.
+        """
+        freq = None
+        if self._can_fast_union(other):
+            freq = self.freq
+        return freq
+
+    def _wrap_joined_index(
+        self, joined, other, lidx: npt.NDArray[np.intp], ridx: npt.NDArray[np.intp]
+    ):
+        assert other.dtype == self.dtype, (other.dtype, self.dtype)
+        result = super()._wrap_joined_index(joined, other, lidx, ridx)
+        result._data._freq = self._get_join_freq(other)
+        return result
+
+    def _get_engine_target(self) -> np.ndarray:
+        # engine methods and libjoin methods need dt64/td64 values cast to i8
+        return self._data._ndarray.view("i8")
+
+    def _from_join_target(self, result: np.ndarray):
+        # view e.g. i8 back to M8[ns]
+        result = result.view(self._data._ndarray.dtype)
+        return self._data._from_backing_data(result)
+
+    # --------------------------------------------------------------------
+    # List-like Methods
+
+    def _get_delete_freq(self, loc: int | slice | Sequence[int]):
+        """
+        Find the `freq` for self.delete(loc).
+        """
+        freq = None
+        if self.freq is not None:
+            if is_integer(loc):
+                if loc in (0, -len(self), -1, len(self) - 1):
+                    freq = self.freq
+            else:
+                if is_list_like(loc):
+                    # error: Incompatible types in assignment (expression has
+                    # type "Union[slice, ndarray]", variable has type
+                    # "Union[int, slice, Sequence[int]]")
+                    loc = lib.maybe_indices_to_slice(  # type: ignore[assignment]
+                        np.asarray(loc, dtype=np.intp), len(self)
+                    )
+                if isinstance(loc, slice) and loc.step in (1, None):
+                    if loc.start in (0, None) or loc.stop in (len(self), None):
+                        freq = self.freq
+        return freq
+
+    def _get_insert_freq(self, loc: int, item):
+        """
+        Find the `freq` for self.insert(loc, item).
+        """
+        value = self._data._validate_scalar(item)
+        item = self._data._box_func(value)
+
+        freq = None
+        if self.freq is not None:
+            # freq can be preserved on edge cases
+            if self.size:
+                if item is NaT:
+                    pass
+                elif loc in (0, -len(self)) and item + self.freq == self[0]:
+                    freq = self.freq
+                elif (loc == len(self)) and item - self.freq == self[-1]:
+                    freq = self.freq
+            else:
+                # Adding a single item to an empty index may preserve freq
+                if isinstance(self.freq, Tick):
+                    # all TimedeltaIndex cases go through here; is_on_offset
+                    #  would raise TypeError
+                    freq = self.freq
+                elif self.freq.is_on_offset(item):
+                    freq = self.freq
+        return freq
+
+    @doc(NDArrayBackedExtensionIndex.delete)
+    def delete(self, loc) -> Self:
+        result = super().delete(loc)
+        result._data._freq = self._get_delete_freq(loc)
+        return result
+
+    @doc(NDArrayBackedExtensionIndex.insert)
+    def insert(self, loc: int, item):
+        result = super().insert(loc, item)
+        if isinstance(result, type(self)):
+            # i.e. parent class method did not cast
+            result._data._freq = self._get_insert_freq(loc, item)
+        return result
+
+    # --------------------------------------------------------------------
+    # NDArray-Like Methods
+
+    @Appender(_index_shared_docs["take"] % _index_doc_kwargs)
+    def take(
+        self,
+        indices,
+        axis: Axis = 0,
+        allow_fill: bool = True,
+        fill_value=None,
+        **kwargs,
+    ) -> Self:
+        nv.validate_take((), kwargs)
+        indices = np.asarray(indices, dtype=np.intp)
+
+        result = NDArrayBackedExtensionIndex.take(
+            self, indices, axis, allow_fill, fill_value, **kwargs
+        )
+
+        maybe_slice = lib.maybe_indices_to_slice(indices, len(self))
+        if isinstance(maybe_slice, slice):
+            freq = self._data._get_getitem_freq(maybe_slice)
+            result._data._freq = freq
+        return result

lib/python3.13/site-packages/pandas/core/indexes/extension.py

@@ -0,0 +1,172 @@
+"""
+Shared methods for Index subclasses backed by ExtensionArray.
+"""
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING,
+    Callable,
+    TypeVar,
+)
+
+from pandas.util._decorators import cache_readonly
+
+from pandas.core.dtypes.generic import ABCDataFrame
+
+from pandas.core.indexes.base import Index
+
+if TYPE_CHECKING:
+    import numpy as np
+
+    from pandas._typing import (
+        ArrayLike,
+        npt,
+    )
+
+    from pandas.core.arrays import IntervalArray
+    from pandas.core.arrays._mixins import NDArrayBackedExtensionArray
+
+_ExtensionIndexT = TypeVar("_ExtensionIndexT", bound="ExtensionIndex")
+
+
+def _inherit_from_data(
+    name: str, delegate: type, cache: bool = False, wrap: bool = False
+):
+    """
+    Make an alias for a method of the underlying ExtensionArray.
+
+    Parameters
+    ----------
+    name : str
+        Name of an attribute the class should inherit from its EA parent.
+    delegate : class
+    cache : bool, default False
+        Whether to convert wrapped properties into cache_readonly
+    wrap : bool, default False
+        Whether to wrap the inherited result in an Index.
+
+    Returns
+    -------
+    attribute, method, property, or cache_readonly
+    """
+    attr = getattr(delegate, name)
+
+    if isinstance(attr, property) or type(attr).__name__ == "getset_descriptor":
+        # getset_descriptor i.e. property defined in cython class
+        if cache:
+
+            def cached(self):
+                return getattr(self._data, name)
+
+            cached.__name__ = name
+            cached.__doc__ = attr.__doc__
+            method = cache_readonly(cached)
+
+        else:
+
+            def fget(self):
+                result = getattr(self._data, name)
+                if wrap:
+                    if isinstance(result, type(self._data)):
+                        return type(self)._simple_new(result, name=self.name)
+                    elif isinstance(result, ABCDataFrame):
+                        return result.set_index(self)
+                    return Index(result, name=self.name)
+                return result
+
+            def fset(self, value) -> None:
+                setattr(self._data, name, value)
+
+            fget.__name__ = name
+            fget.__doc__ = attr.__doc__
+
+            method = property(fget, fset)
+
+    elif not callable(attr):
+        # just a normal attribute, no wrapping
+        method = attr
+
+    else:
+        # error: Incompatible redefinition (redefinition with type "Callable[[Any,
+        # VarArg(Any), KwArg(Any)], Any]", original type "property")
+        def method(self, *args, **kwargs):  # type: ignore[misc]
+            if "inplace" in kwargs:
+                raise ValueError(f"cannot use inplace with {type(self).__name__}")
+            result = attr(self._data, *args, **kwargs)
+            if wrap:
+                if isinstance(result, type(self._data)):
+                    return type(self)._simple_new(result, name=self.name)
+                elif isinstance(result, ABCDataFrame):
+                    return result.set_index(self)
+                return Index(result, name=self.name)
+            return result
+
+        # error: "property" has no attribute "__name__"
+        method.__name__ = name  # type: ignore[attr-defined]
+        method.__doc__ = attr.__doc__
+    return method
+
+
+def inherit_names(
+    names: list[str], delegate: type, cache: bool = False, wrap: bool = False
+) -> Callable[[type[_ExtensionIndexT]], type[_ExtensionIndexT]]:
+    """
+    Class decorator to pin attributes from an ExtensionArray to a Index subclass.
+
+    Parameters
+    ----------
+    names : List[str]
+    delegate : class
+    cache : bool, default False
+    wrap : bool, default False
+        Whether to wrap the inherited result in an Index.
+    """
+
+    def wrapper(cls: type[_ExtensionIndexT]) -> type[_ExtensionIndexT]:
+        for name in names:
+            meth = _inherit_from_data(name, delegate, cache=cache, wrap=wrap)
+            setattr(cls, name, meth)
+
+        return cls
+
+    return wrapper
+
+
+class ExtensionIndex(Index):
+    """
+    Index subclass for indexes backed by ExtensionArray.
+    """
+
+    # The base class already passes through to _data:
+    #  size, __len__, dtype
+
+    _data: IntervalArray | NDArrayBackedExtensionArray
+
+    # ---------------------------------------------------------------------
+
+    def _validate_fill_value(self, value):
+        """
+        Convert value to be insertable to underlying array.
+        """
+        return self._data._validate_setitem_value(value)
+
+    @cache_readonly
+    def _isnan(self) -> npt.NDArray[np.bool_]:
+        # error: Incompatible return value type (got "ExtensionArray", expected
+        # "ndarray")
+        return self._data.isna()  # type: ignore[return-value]
+
+
+class NDArrayBackedExtensionIndex(ExtensionIndex):
+    """
+    Index subclass for indexes backed by NDArrayBackedExtensionArray.
+    """
+
+    _data: NDArrayBackedExtensionArray
+
+    def _get_engine_target(self) -> np.ndarray:
+        return self._data._ndarray
+
+    def _from_join_target(self, result: np.ndarray) -> ArrayLike:
+        assert result.dtype == self._data._ndarray.dtype
+        return self._data._from_backing_data(result)

lib/python3.13/site-packages/pandas/core/indexes/frozen.py

@@ -0,0 +1,120 @@
+"""
+frozen (immutable) data structures to support MultiIndexing
+
+These are used for:
+
+- .names (FrozenList)
+
+"""
+from __future__ import annotations
+
+from typing import (
+    TYPE_CHECKING,
+    NoReturn,
+)
+
+from pandas.core.base import PandasObject
+
+from pandas.io.formats.printing import pprint_thing
+
+if TYPE_CHECKING:
+    from pandas._typing import Self
+
+
+class FrozenList(PandasObject, list):
+    """
+    Container that doesn't allow setting item *but*
+    because it's technically hashable, will be used
+    for lookups, appropriately, etc.
+    """
+
+    # Side note: This has to be of type list. Otherwise,
+    #            it messes up PyTables type checks.
+
+    def union(self, other) -> FrozenList:
+        """
+        Returns a FrozenList with other concatenated to the end of self.
+
+        Parameters
+        ----------
+        other : array-like
+            The array-like whose elements we are concatenating.
+
+        Returns
+        -------
+        FrozenList
+            The collection difference between self and other.
+        """
+        if isinstance(other, tuple):
+            other = list(other)
+        return type(self)(super().__add__(other))
+
+    def difference(self, other) -> FrozenList:
+        """
+        Returns a FrozenList with elements from other removed from self.
+
+        Parameters
+        ----------
+        other : array-like
+            The array-like whose elements we are removing self.
+
+        Returns
+        -------
+        FrozenList
+            The collection difference between self and other.
+        """
+        other = set(other)
+        temp = [x for x in self if x not in other]
+        return type(self)(temp)
+
+    # TODO: Consider deprecating these in favor of `union` (xref gh-15506)
+    # error: Incompatible types in assignment (expression has type
+    # "Callable[[FrozenList, Any], FrozenList]", base class "list" defined the
+    # type as overloaded function)
+    __add__ = __iadd__ = union  # type: ignore[assignment]
+
+    def __getitem__(self, n):
+        if isinstance(n, slice):
+            return type(self)(super().__getitem__(n))
+        return super().__getitem__(n)
+
+    def __radd__(self, other) -> Self:
+        if isinstance(other, tuple):
+            other = list(other)
+        return type(self)(other + list(self))
+
+    def __eq__(self, other: object) -> bool:
+        if isinstance(other, (tuple, FrozenList)):
+            other = list(other)
+        return super().__eq__(other)
+
+    __req__ = __eq__
+
+    def __mul__(self, other) -> Self:
+        return type(self)(super().__mul__(other))
+
+    __imul__ = __mul__
+
+    def __reduce__(self):
+        return type(self), (list(self),)
+
+    # error: Signature of "__hash__" incompatible with supertype "list"
+    def __hash__(self) -> int:  # type: ignore[override]
+        return hash(tuple(self))
+
+    def _disabled(self, *args, **kwargs) -> NoReturn:
+        """
+        This method will not function because object is immutable.
+        """
+        raise TypeError(f"'{type(self).__name__}' does not support mutable operations.")
+
+    def __str__(self) -> str:
+        return pprint_thing(self, quote_strings=True, escape_chars=("\t", "\r", "\n"))
+
+    def __repr__(self) -> str:
+        return f"{type(self).__name__}({str(self)})"
+
+    __setitem__ = __setslice__ = _disabled  # type: ignore[assignment]
+    __delitem__ = __delslice__ = _disabled
+    pop = append = extend = _disabled
+    remove = sort = insert = _disabled  # type: ignore[assignment]

lib/python3.13/site-packages/pandas/core/indexes/period.py

@@ -0,0 +1,614 @@
+from __future__ import annotations
+
+from datetime import (
+    datetime,
+    timedelta,
+)
+from typing import TYPE_CHECKING
+import warnings
+
+import numpy as np
+
+from pandas._libs import index as libindex
+from pandas._libs.tslibs import (
+    BaseOffset,
+    NaT,
+    Period,
+    Resolution,
+    Tick,
+)
+from pandas._libs.tslibs.dtypes import OFFSET_TO_PERIOD_FREQSTR
+from pandas.util._decorators import (
+    cache_readonly,
+    doc,
+)
+from pandas.util._exceptions import find_stack_level
+
+from pandas.core.dtypes.common import is_integer
+from pandas.core.dtypes.dtypes import PeriodDtype
+from pandas.core.dtypes.generic import ABCSeries
+from pandas.core.dtypes.missing import is_valid_na_for_dtype
+
+from pandas.core.arrays.period import (
+    PeriodArray,
+    period_array,
+    raise_on_incompatible,
+    validate_dtype_freq,
+)
+import pandas.core.common as com
+import pandas.core.indexes.base as ibase
+from pandas.core.indexes.base import maybe_extract_name
+from pandas.core.indexes.datetimelike import DatetimeIndexOpsMixin
+from pandas.core.indexes.datetimes import (
+    DatetimeIndex,
+    Index,
+)
+from pandas.core.indexes.extension import inherit_names
+
+if TYPE_CHECKING:
+    from collections.abc import Hashable
+
+    from pandas._typing import (
+        Dtype,
+        DtypeObj,
+        Self,
+        npt,
+    )
+
+
+_index_doc_kwargs = dict(ibase._index_doc_kwargs)
+_index_doc_kwargs.update({"target_klass": "PeriodIndex or list of Periods"})
+_shared_doc_kwargs = {
+    "klass": "PeriodArray",
+}
+
+# --- Period index sketch
+
+
+def _new_PeriodIndex(cls, **d):
+    # GH13277 for unpickling
+    values = d.pop("data")
+    if values.dtype == "int64":
+        freq = d.pop("freq", None)
+        dtype = PeriodDtype(freq)
+        values = PeriodArray(values, dtype=dtype)
+        return cls._simple_new(values, **d)
+    else:
+        return cls(values, **d)
+
+
+@inherit_names(
+    ["strftime", "start_time", "end_time"] + PeriodArray._field_ops,
+    PeriodArray,
+    wrap=True,
+)
+@inherit_names(["is_leap_year"], PeriodArray)
+class PeriodIndex(DatetimeIndexOpsMixin):
+    """
+    Immutable ndarray holding ordinal values indicating regular periods in time.
+
+    Index keys are boxed to Period objects which carries the metadata (eg,
+    frequency information).
+
+    Parameters
+    ----------
+    data : array-like (1d int np.ndarray or PeriodArray), optional
+        Optional period-like data to construct index with.
+    copy : bool
+        Make a copy of input ndarray.
+    freq : str or period object, optional
+        One of pandas period strings or corresponding objects.
+    year : int, array, or Series, default None
+
+        .. deprecated:: 2.2.0
+           Use PeriodIndex.from_fields instead.
+    month : int, array, or Series, default None
+
+        .. deprecated:: 2.2.0
+           Use PeriodIndex.from_fields instead.
+    quarter : int, array, or Series, default None
+
+        .. deprecated:: 2.2.0
+           Use PeriodIndex.from_fields instead.
+    day : int, array, or Series, default None
+
+        .. deprecated:: 2.2.0
+           Use PeriodIndex.from_fields instead.
+    hour : int, array, or Series, default None
+
+        .. deprecated:: 2.2.0
+           Use PeriodIndex.from_fields instead.
+    minute : int, array, or Series, default None
+
+        .. deprecated:: 2.2.0
+           Use PeriodIndex.from_fields instead.
+    second : int, array, or Series, default None
+
+        .. deprecated:: 2.2.0
+           Use PeriodIndex.from_fields instead.
+    dtype : str or PeriodDtype, default None
+
+    Attributes
+    ----------
+    day
+    dayofweek
+    day_of_week
+    dayofyear
+    day_of_year
+    days_in_month
+    daysinmonth
+    end_time
+    freq
+    freqstr
+    hour
+    is_leap_year
+    minute
+    month
+    quarter
+    qyear
+    second
+    start_time
+    week
+    weekday
+    weekofyear
+    year
+
+    Methods
+    -------
+    asfreq
+    strftime
+    to_timestamp
+    from_fields
+    from_ordinals
+
+    See Also
+    --------
+    Index : The base pandas Index type.
+    Period : Represents a period of time.
+    DatetimeIndex : Index with datetime64 data.
+    TimedeltaIndex : Index of timedelta64 data.
+    period_range : Create a fixed-frequency PeriodIndex.
+
+    Examples
+    --------
+    >>> idx = pd.PeriodIndex.from_fields(year=[2000, 2002], quarter=[1, 3])
+    >>> idx
+    PeriodIndex(['2000Q1', '2002Q3'], dtype='period[Q-DEC]')
+    """
+
+    _typ = "periodindex"
+
+    _data: PeriodArray
+    freq: BaseOffset
+    dtype: PeriodDtype
+
+    _data_cls = PeriodArray
+    _supports_partial_string_indexing = True
+
+    @property
+    def _engine_type(self) -> type[libindex.PeriodEngine]:
+        return libindex.PeriodEngine
+
+    @cache_readonly
+    def _resolution_obj(self) -> Resolution:
+        # for compat with DatetimeIndex
+        return self.dtype._resolution_obj
+
+    # --------------------------------------------------------------------
+    # methods that dispatch to array and wrap result in Index
+    # These are defined here instead of via inherit_names for mypy
+
+    @doc(
+        PeriodArray.asfreq,
+        other="pandas.arrays.PeriodArray",
+        other_name="PeriodArray",
+        **_shared_doc_kwargs,
+    )
+    def asfreq(self, freq=None, how: str = "E") -> Self:
+        arr = self._data.asfreq(freq, how)
+        return type(self)._simple_new(arr, name=self.name)
+
+    @doc(PeriodArray.to_timestamp)
+    def to_timestamp(self, freq=None, how: str = "start") -> DatetimeIndex:
+        arr = self._data.to_timestamp(freq, how)
+        return DatetimeIndex._simple_new(arr, name=self.name)
+
+    @property
+    @doc(PeriodArray.hour.fget)
+    def hour(self) -> Index:
+        return Index(self._data.hour, name=self.name)
+
+    @property
+    @doc(PeriodArray.minute.fget)
+    def minute(self) -> Index:
+        return Index(self._data.minute, name=self.name)
+
+    @property
+    @doc(PeriodArray.second.fget)
+    def second(self) -> Index:
+        return Index(self._data.second, name=self.name)
+
+    # ------------------------------------------------------------------------
+    # Index Constructors
+
+    def __new__(
+        cls,
+        data=None,
+        ordinal=None,
+        freq=None,
+        dtype: Dtype | None = None,
+        copy: bool = False,
+        name: Hashable | None = None,
+        **fields,
+    ) -> Self:
+        valid_field_set = {
+            "year",
+            "month",
+            "day",
+            "quarter",
+            "hour",
+            "minute",
+            "second",
+        }
+
+        refs = None
+        if not copy and isinstance(data, (Index, ABCSeries)):
+            refs = data._references
+
+        if not set(fields).issubset(valid_field_set):
+            argument = next(iter(set(fields) - valid_field_set))
+            raise TypeError(f"__new__() got an unexpected keyword argument {argument}")
+        elif len(fields):
+            # GH#55960
+            warnings.warn(
+                "Constructing PeriodIndex from fields is deprecated. Use "
+                "PeriodIndex.from_fields instead.",
+                FutureWarning,
+                stacklevel=find_stack_level(),
+            )
+
+        if ordinal is not None:
+            # GH#55960
+            warnings.warn(
+                "The 'ordinal' keyword in PeriodIndex is deprecated and will "
+                "be removed in a future version. Use PeriodIndex.from_ordinals "
+                "instead.",
+                FutureWarning,
+                stacklevel=find_stack_level(),
+            )
+
+        name = maybe_extract_name(name, data, cls)
+
+        if data is None and ordinal is None:
+            # range-based.
+            if not fields:
+                # test_pickle_compat_construction
+                cls._raise_scalar_data_error(None)
+            data = cls.from_fields(**fields, freq=freq)._data
+            copy = False
+
+        elif fields:
+            if data is not None:
+                raise ValueError("Cannot pass both data and fields")
+            raise ValueError("Cannot pass both ordinal and fields")
+
+        else:
+            freq = validate_dtype_freq(dtype, freq)
+
+            # PeriodIndex allow PeriodIndex(period_index, freq=different)
+            # Let's not encourage that kind of behavior in PeriodArray.
+
+            if freq and isinstance(data, cls) and data.freq != freq:
+                # TODO: We can do some of these with no-copy / coercion?
+                # e.g. D -> 2D seems to be OK
+                data = data.asfreq(freq)
+
+            if data is None and ordinal is not None:
+                ordinal = np.asarray(ordinal, dtype=np.int64)
+                dtype = PeriodDtype(freq)
+                data = PeriodArray(ordinal, dtype=dtype)
+            elif data is not None and ordinal is not None:
+                raise ValueError("Cannot pass both data and ordinal")
+            else:
+                # don't pass copy here, since we copy later.
+                data = period_array(data=data, freq=freq)
+
+        if copy:
+            data = data.copy()
+
+        return cls._simple_new(data, name=name, refs=refs)
+
+    @classmethod
+    def from_fields(
+        cls,
+        *,
+        year=None,
+        quarter=None,
+        month=None,
+        day=None,
+        hour=None,
+        minute=None,
+        second=None,
+        freq=None,
+    ) -> Self:
+        fields = {
+            "year": year,
+            "quarter": quarter,
+            "month": month,
+            "day": day,
+            "hour": hour,
+            "minute": minute,
+            "second": second,
+        }
+        fields = {key: value for key, value in fields.items() if value is not None}
+        arr = PeriodArray._from_fields(fields=fields, freq=freq)
+        return cls._simple_new(arr)
+
+    @classmethod
+    def from_ordinals(cls, ordinals, *, freq, name=None) -> Self:
+        ordinals = np.asarray(ordinals, dtype=np.int64)
+        dtype = PeriodDtype(freq)
+        data = PeriodArray._simple_new(ordinals, dtype=dtype)
+        return cls._simple_new(data, name=name)
+
+    # ------------------------------------------------------------------------
+    # Data
+
+    @property
+    def values(self) -> npt.NDArray[np.object_]:
+        return np.asarray(self, dtype=object)
+
+    def _maybe_convert_timedelta(self, other) -> int | npt.NDArray[np.int64]:
+        """
+        Convert timedelta-like input to an integer multiple of self.freq
+
+        Parameters
+        ----------
+        other : timedelta, np.timedelta64, DateOffset, int, np.ndarray
+
+        Returns
+        -------
+        converted : int, np.ndarray[int64]
+
+        Raises
+        ------
+        IncompatibleFrequency : if the input cannot be written as a multiple
+            of self.freq.  Note IncompatibleFrequency subclasses ValueError.
+        """
+        if isinstance(other, (timedelta, np.timedelta64, Tick, np.ndarray)):
+            if isinstance(self.freq, Tick):
+                # _check_timedeltalike_freq_compat will raise if incompatible
+                delta = self._data._check_timedeltalike_freq_compat(other)
+                return delta
+        elif isinstance(other, BaseOffset):
+            if other.base == self.freq.base:
+                return other.n
+
+            raise raise_on_incompatible(self, other)
+        elif is_integer(other):
+            assert isinstance(other, int)
+            return other
+
+        # raise when input doesn't have freq
+        raise raise_on_incompatible(self, None)
+
+    def _is_comparable_dtype(self, dtype: DtypeObj) -> bool:
+        """
+        Can we compare values of the given dtype to our own?
+        """
+        return self.dtype == dtype
+
+    # ------------------------------------------------------------------------
+    # Index Methods
+
+    def asof_locs(self, where: Index, mask: npt.NDArray[np.bool_]) -> np.ndarray:
+        """
+        where : array of timestamps
+        mask : np.ndarray[bool]
+            Array of booleans where data is not NA.
+        """
+        if isinstance(where, DatetimeIndex):
+            where = PeriodIndex(where._values, freq=self.freq)
+        elif not isinstance(where, PeriodIndex):
+            raise TypeError("asof_locs `where` must be DatetimeIndex or PeriodIndex")
+
+        return super().asof_locs(where, mask)
+
+    @property
+    def is_full(self) -> bool:
+        """
+        Returns True if this PeriodIndex is range-like in that all Periods
+        between start and end are present, in order.
+        """
+        if len(self) == 0:
+            return True
+        if not self.is_monotonic_increasing:
+            raise ValueError("Index is not monotonic")
+        values = self.asi8
+        return bool(((values[1:] - values[:-1]) < 2).all())
+
+    @property
+    def inferred_type(self) -> str:
+        # b/c data is represented as ints make sure we can't have ambiguous
+        # indexing
+        return "period"
+
+    # ------------------------------------------------------------------------
+    # Indexing Methods
+
+    def _convert_tolerance(self, tolerance, target):
+        # Returned tolerance must be in dtype/units so that
+        #  `|self._get_engine_target() - target._engine_target()| <= tolerance`
+        #  is meaningful.  Since PeriodIndex returns int64 for engine_target,
+        #  we may need to convert timedelta64 tolerance to int64.
+        tolerance = super()._convert_tolerance(tolerance, target)
+
+        if self.dtype == target.dtype:
+            # convert tolerance to i8
+            tolerance = self._maybe_convert_timedelta(tolerance)
+
+        return tolerance
+
+    def get_loc(self, key):
+        """
+        Get integer location for requested label.
+
+        Parameters
+        ----------
+        key : Period, NaT, str, or datetime
+            String or datetime key must be parsable as Period.
+
+        Returns
+        -------
+        loc : int or ndarray[int64]
+
+        Raises
+        ------
+        KeyError
+            Key is not present in the index.
+        TypeError
+            If key is listlike or otherwise not hashable.
+        """
+        orig_key = key
+
+        self._check_indexing_error(key)
+
+        if is_valid_na_for_dtype(key, self.dtype):
+            key = NaT
+
+        elif isinstance(key, str):
+            try:
+                parsed, reso = self._parse_with_reso(key)
+            except ValueError as err:
+                # A string with invalid format
+                raise KeyError(f"Cannot interpret '{key}' as period") from err
+
+            if self._can_partial_date_slice(reso):
+                try:
+                    return self._partial_date_slice(reso, parsed)
+                except KeyError as err:
+                    raise KeyError(key) from err
+
+            if reso == self._resolution_obj:
+                # the reso < self._resolution_obj case goes
+                #  through _get_string_slice
+                key = self._cast_partial_indexing_scalar(parsed)
+            else:
+                raise KeyError(key)
+
+        elif isinstance(key, Period):
+            self._disallow_mismatched_indexing(key)
+
+        elif isinstance(key, datetime):
+            key = self._cast_partial_indexing_scalar(key)
+
+        else:
+            # in particular integer, which Period constructor would cast to string
+            raise KeyError(key)
+
+        try:
+            return Index.get_loc(self, key)
+        except KeyError as err:
+            raise KeyError(orig_key) from err
+
+    def _disallow_mismatched_indexing(self, key: Period) -> None:
+        if key._dtype != self.dtype:
+            raise KeyError(key)
+
+    def _cast_partial_indexing_scalar(self, label: datetime) -> Period:
+        try:
+            period = Period(label, freq=self.freq)
+        except ValueError as err:
+            # we cannot construct the Period
+            raise KeyError(label) from err
+        return period
+
+    @doc(DatetimeIndexOpsMixin._maybe_cast_slice_bound)
+    def _maybe_cast_slice_bound(self, label, side: str):
+        if isinstance(label, datetime):
+            label = self._cast_partial_indexing_scalar(label)
+
+        return super()._maybe_cast_slice_bound(label, side)
+
+    def _parsed_string_to_bounds(self, reso: Resolution, parsed: datetime):
+        freq = OFFSET_TO_PERIOD_FREQSTR.get(reso.attr_abbrev, reso.attr_abbrev)
+        iv = Period(parsed, freq=freq)
+        return (iv.asfreq(self.freq, how="start"), iv.asfreq(self.freq, how="end"))
+
+    @doc(DatetimeIndexOpsMixin.shift)
+    def shift(self, periods: int = 1, freq=None) -> Self:
+        if freq is not None:
+            raise TypeError(
+                f"`freq` argument is not supported for {type(self).__name__}.shift"
+            )
+        return self + periods
+
+
+def period_range(
+    start=None,
+    end=None,
+    periods: int | None = None,
+    freq=None,
+    name: Hashable | None = None,
+) -> PeriodIndex:
+    """
+    Return a fixed frequency PeriodIndex.
+
+    The day (calendar) is the default frequency.
+
+    Parameters
+    ----------
+    start : str, datetime, date, pandas.Timestamp, or period-like, default None
+        Left bound for generating periods.
+    end : str, datetime, date, pandas.Timestamp, or period-like, default None
+        Right bound for generating periods.
+    periods : int, default None
+        Number of periods to generate.
+    freq : str or DateOffset, optional
+        Frequency alias. By default the freq is taken from `start` or `end`
+        if those are Period objects. Otherwise, the default is ``"D"`` for
+        daily frequency.
+    name : str, default None
+        Name of the resulting PeriodIndex.
+
+    Returns
+    -------
+    PeriodIndex
+
+    Notes
+    -----
+    Of the three parameters: ``start``, ``end``, and ``periods``, exactly two
+    must be specified.
+
+    To learn more about the frequency strings, please see `this link
+    <https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`__.
+
+    Examples
+    --------
+    >>> pd.period_range(start='2017-01-01', end='2018-01-01', freq='M')
+    PeriodIndex(['2017-01', '2017-02', '2017-03', '2017-04', '2017-05', '2017-06',
+             '2017-07', '2017-08', '2017-09', '2017-10', '2017-11', '2017-12',
+             '2018-01'],
+            dtype='period[M]')
+
+    If ``start`` or ``end`` are ``Period`` objects, they will be used as anchor
+    endpoints for a ``PeriodIndex`` with frequency matching that of the
+    ``period_range`` constructor.
+
+    >>> pd.period_range(start=pd.Period('2017Q1', freq='Q'),
+    ...                 end=pd.Period('2017Q2', freq='Q'), freq='M')
+    PeriodIndex(['2017-03', '2017-04', '2017-05', '2017-06'],
+                dtype='period[M]')
+    """
+    if com.count_not_none(start, end, periods) != 2:
+        raise ValueError(
+            "Of the three parameters: start, end, and periods, "
+            "exactly two must be specified"
+        )
+    if freq is None and (not isinstance(start, Period) and not isinstance(end, Period)):
+        freq = "D"
+
+    data, freq = PeriodArray._generate_range(start, end, periods, freq)
+    dtype = PeriodDtype(freq)
+    data = PeriodArray(data, dtype=dtype)
+    return PeriodIndex(data, name=name)

lib/python3.13/site-packages/pandas/core/indexes/timedeltas.py

@@ -0,0 +1,356 @@
+""" implement the TimedeltaIndex """
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+import warnings
+
+from pandas._libs import (
+    index as libindex,
+    lib,
+)
+from pandas._libs.tslibs import (
+    Resolution,
+    Timedelta,
+    to_offset,
+)
+from pandas._libs.tslibs.timedeltas import disallow_ambiguous_unit
+from pandas.util._exceptions import find_stack_level
+
+from pandas.core.dtypes.common import (
+    is_scalar,
+    pandas_dtype,
+)
+from pandas.core.dtypes.generic import ABCSeries
+
+from pandas.core.arrays.timedeltas import TimedeltaArray
+import pandas.core.common as com
+from pandas.core.indexes.base import (
+    Index,
+    maybe_extract_name,
+)
+from pandas.core.indexes.datetimelike import DatetimeTimedeltaMixin
+from pandas.core.indexes.extension import inherit_names
+
+if TYPE_CHECKING:
+    from pandas._typing import DtypeObj
+
+
+@inherit_names(
+    ["__neg__", "__pos__", "__abs__", "total_seconds", "round", "floor", "ceil"]
+    + TimedeltaArray._field_ops,
+    TimedeltaArray,
+    wrap=True,
+)
+@inherit_names(
+    [
+        "components",
+        "to_pytimedelta",
+        "sum",
+        "std",
+        "median",
+    ],
+    TimedeltaArray,
+)
+class TimedeltaIndex(DatetimeTimedeltaMixin):
+    """
+    Immutable Index of timedelta64 data.
+
+    Represented internally as int64, and scalars returned Timedelta objects.
+
+    Parameters
+    ----------
+    data : array-like (1-dimensional), optional
+        Optional timedelta-like data to construct index with.
+    unit : {'D', 'h', 'm', 's', 'ms', 'us', 'ns'}, optional
+        The unit of ``data``.
+
+        .. deprecated:: 2.2.0
+         Use ``pd.to_timedelta`` instead.
+
+    freq : str or pandas offset object, optional
+        One of pandas date offset strings or corresponding objects. The string
+        ``'infer'`` can be passed in order to set the frequency of the index as
+        the inferred frequency upon creation.
+    dtype : numpy.dtype or str, default None
+        Valid ``numpy`` dtypes are ``timedelta64[ns]``, ``timedelta64[us]``,
+        ``timedelta64[ms]``, and ``timedelta64[s]``.
+    copy : bool
+        Make a copy of input array.
+    name : object
+        Name to be stored in the index.
+
+    Attributes
+    ----------
+    days
+    seconds
+    microseconds
+    nanoseconds
+    components
+    inferred_freq
+
+    Methods
+    -------
+    to_pytimedelta
+    to_series
+    round
+    floor
+    ceil
+    to_frame
+    mean
+
+    See Also
+    --------
+    Index : The base pandas Index type.
+    Timedelta : Represents a duration between two dates or times.
+    DatetimeIndex : Index of datetime64 data.
+    PeriodIndex : Index of Period data.
+    timedelta_range : Create a fixed-frequency TimedeltaIndex.
+
+    Notes
+    -----
+    To learn more about the frequency strings, please see `this link
+    <https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`__.
+
+    Examples
+    --------
+    >>> pd.TimedeltaIndex(['0 days', '1 days', '2 days', '3 days', '4 days'])
+    TimedeltaIndex(['0 days', '1 days', '2 days', '3 days', '4 days'],
+                   dtype='timedelta64[ns]', freq=None)
+
+    We can also let pandas infer the frequency when possible.
+
+    >>> pd.TimedeltaIndex(np.arange(5) * 24 * 3600 * 1e9, freq='infer')
+    TimedeltaIndex(['0 days', '1 days', '2 days', '3 days', '4 days'],
+                   dtype='timedelta64[ns]', freq='D')
+    """
+
+    _typ = "timedeltaindex"
+
+    _data_cls = TimedeltaArray
+
+    @property
+    def _engine_type(self) -> type[libindex.TimedeltaEngine]:
+        return libindex.TimedeltaEngine
+
+    _data: TimedeltaArray
+
+    # Use base class method instead of DatetimeTimedeltaMixin._get_string_slice
+    _get_string_slice = Index._get_string_slice
+
+    # error: Signature of "_resolution_obj" incompatible with supertype
+    # "DatetimeIndexOpsMixin"
+    @property
+    def _resolution_obj(self) -> Resolution | None:  # type: ignore[override]
+        return self._data._resolution_obj
+
+    # -------------------------------------------------------------------
+    # Constructors
+
+    def __new__(
+        cls,
+        data=None,
+        unit=lib.no_default,
+        freq=lib.no_default,
+        closed=lib.no_default,
+        dtype=None,
+        copy: bool = False,
+        name=None,
+    ):
+        if closed is not lib.no_default:
+            # GH#52628
+            warnings.warn(
+                f"The 'closed' keyword in {cls.__name__} construction is "
+                "deprecated and will be removed in a future version.",
+                FutureWarning,
+                stacklevel=find_stack_level(),
+            )
+
+        if unit is not lib.no_default:
+            # GH#55499
+            warnings.warn(
+                f"The 'unit' keyword in {cls.__name__} construction is "
+                "deprecated and will be removed in a future version. "
+                "Use pd.to_timedelta instead.",
+                FutureWarning,
+                stacklevel=find_stack_level(),
+            )
+        else:
+            unit = None
+
+        name = maybe_extract_name(name, data, cls)
+
+        if is_scalar(data):
+            cls._raise_scalar_data_error(data)
+
+        disallow_ambiguous_unit(unit)
+        if dtype is not None:
+            dtype = pandas_dtype(dtype)
+
+        if (
+            isinstance(data, TimedeltaArray)
+            and freq is lib.no_default
+            and (dtype is None or dtype == data.dtype)
+        ):
+            if copy:
+                data = data.copy()
+            return cls._simple_new(data, name=name)
+
+        if (
+            isinstance(data, TimedeltaIndex)
+            and freq is lib.no_default
+            and name is None
+            and (dtype is None or dtype == data.dtype)
+        ):
+            if copy:
+                return data.copy()
+            else:
+                return data._view()
+
+        # - Cases checked above all return/raise before reaching here - #
+
+        tdarr = TimedeltaArray._from_sequence_not_strict(
+            data, freq=freq, unit=unit, dtype=dtype, copy=copy
+        )
+        refs = None
+        if not copy and isinstance(data, (ABCSeries, Index)):
+            refs = data._references
+
+        return cls._simple_new(tdarr, name=name, refs=refs)
+
+    # -------------------------------------------------------------------
+
+    def _is_comparable_dtype(self, dtype: DtypeObj) -> bool:
+        """
+        Can we compare values of the given dtype to our own?
+        """
+        return lib.is_np_dtype(dtype, "m")  # aka self._data._is_recognized_dtype
+
+    # -------------------------------------------------------------------
+    # Indexing Methods
+
+    def get_loc(self, key):
+        """
+        Get integer location for requested label
+
+        Returns
+        -------
+        loc : int, slice, or ndarray[int]
+        """
+        self._check_indexing_error(key)
+
+        try:
+            key = self._data._validate_scalar(key, unbox=False)
+        except TypeError as err:
+            raise KeyError(key) from err
+
+        return Index.get_loc(self, key)
+
+    def _parse_with_reso(self, label: str):
+        # the "with_reso" is a no-op for TimedeltaIndex
+        parsed = Timedelta(label)
+        return parsed, None
+
+    def _parsed_string_to_bounds(self, reso, parsed: Timedelta):
+        # reso is unused, included to match signature of DTI/PI
+        lbound = parsed.round(parsed.resolution_string)
+        rbound = lbound + to_offset(parsed.resolution_string) - Timedelta(1, "ns")
+        return lbound, rbound
+
+    # -------------------------------------------------------------------
+
+    @property
+    def inferred_type(self) -> str:
+        return "timedelta64"
+
+
+def timedelta_range(
+    start=None,
+    end=None,
+    periods: int | None = None,
+    freq=None,
+    name=None,
+    closed=None,
+    *,
+    unit: str | None = None,
+) -> TimedeltaIndex:
+    """
+    Return a fixed frequency TimedeltaIndex with day as the default.
+
+    Parameters
+    ----------
+    start : str or timedelta-like, default None
+        Left bound for generating timedeltas.
+    end : str or timedelta-like, default None
+        Right bound for generating timedeltas.
+    periods : int, default None
+        Number of periods to generate.
+    freq : str, Timedelta, datetime.timedelta, or DateOffset, default 'D'
+        Frequency strings can have multiples, e.g. '5h'.
+    name : str, default None
+        Name of the resulting TimedeltaIndex.
+    closed : str, default None
+        Make the interval closed with respect to the given frequency to
+        the 'left', 'right', or both sides (None).
+    unit : str, default None
+        Specify the desired resolution of the result.
+
+        .. versionadded:: 2.0.0
+
+    Returns
+    -------
+    TimedeltaIndex
+
+    Notes
+    -----
+    Of the four parameters ``start``, ``end``, ``periods``, and ``freq``,
+    exactly three must be specified. If ``freq`` is omitted, the resulting
+    ``TimedeltaIndex`` will have ``periods`` linearly spaced elements between
+    ``start`` and ``end`` (closed on both sides).
+
+    To learn more about the frequency strings, please see `this link
+    <https://pandas.pydata.org/pandas-docs/stable/user_guide/timeseries.html#offset-aliases>`__.
+
+    Examples
+    --------
+    >>> pd.timedelta_range(start='1 day', periods=4)
+    TimedeltaIndex(['1 days', '2 days', '3 days', '4 days'],
+                   dtype='timedelta64[ns]', freq='D')
+
+    The ``closed`` parameter specifies which endpoint is included.  The default
+    behavior is to include both endpoints.
+
+    >>> pd.timedelta_range(start='1 day', periods=4, closed='right')
+    TimedeltaIndex(['2 days', '3 days', '4 days'],
+                   dtype='timedelta64[ns]', freq='D')
+
+    The ``freq`` parameter specifies the frequency of the TimedeltaIndex.
+    Only fixed frequencies can be passed, non-fixed frequencies such as
+    'M' (month end) will raise.
+
+    >>> pd.timedelta_range(start='1 day', end='2 days', freq='6h')
+    TimedeltaIndex(['1 days 00:00:00', '1 days 06:00:00', '1 days 12:00:00',
+                    '1 days 18:00:00', '2 days 00:00:00'],
+                   dtype='timedelta64[ns]', freq='6h')
+
+    Specify ``start``, ``end``, and ``periods``; the frequency is generated
+    automatically (linearly spaced).
+
+    >>> pd.timedelta_range(start='1 day', end='5 days', periods=4)
+    TimedeltaIndex(['1 days 00:00:00', '2 days 08:00:00', '3 days 16:00:00',
+                    '5 days 00:00:00'],
+                   dtype='timedelta64[ns]', freq=None)
+
+    **Specify a unit**
+
+    >>> pd.timedelta_range("1 Day", periods=3, freq="100000D", unit="s")
+    TimedeltaIndex(['1 days', '100001 days', '200001 days'],
+                   dtype='timedelta64[s]', freq='100000D')
+    """
+    if freq is None and com.any_none(periods, start, end):
+        freq = "D"
+
+    freq = to_offset(freq)
+    tdarr = TimedeltaArray._generate_range(
+        start, end, periods, freq, closed=closed, unit=unit
+    )
+    return TimedeltaIndex._simple_new(tdarr, name=name)