439 lines
16 KiB
Python
439 lines
16 KiB
Python
from __future__ import annotations
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from functools import lru_cache
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from typing import TYPE_CHECKING, Any, cast
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import pyarrow as pa
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import pyarrow.compute as pc
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from narwhals._compliant import EagerSeriesNamespace
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from narwhals._utils import Version, isinstance_or_issubclass
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if TYPE_CHECKING:
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from collections.abc import Iterable, Iterator, Mapping
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from typing_extensions import TypeAlias, TypeIs
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from narwhals._arrow.series import ArrowSeries
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from narwhals._arrow.typing import (
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ArrayAny,
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ArrayOrScalar,
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ArrayOrScalarT1,
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ArrayOrScalarT2,
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ChunkedArrayAny,
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NativeIntervalUnit,
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ScalarAny,
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)
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from narwhals._duration import IntervalUnit
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from narwhals.dtypes import DType
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from narwhals.typing import IntoDType, PythonLiteral
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# NOTE: stubs don't allow for `ChunkedArray[StructArray]`
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# Intended to represent the `.chunks` property storing `list[pa.StructArray]`
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ChunkedArrayStructArray: TypeAlias = ChunkedArrayAny
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def is_timestamp(t: Any) -> TypeIs[pa.TimestampType[Any, Any]]: ...
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def is_duration(t: Any) -> TypeIs[pa.DurationType[Any]]: ...
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def is_list(t: Any) -> TypeIs[pa.ListType[Any]]: ...
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def is_large_list(t: Any) -> TypeIs[pa.LargeListType[Any]]: ...
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def is_fixed_size_list(t: Any) -> TypeIs[pa.FixedSizeListType[Any, Any]]: ...
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def is_dictionary(t: Any) -> TypeIs[pa.DictionaryType[Any, Any, Any]]: ...
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def extract_regex(
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strings: ChunkedArrayAny,
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/,
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pattern: str,
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*,
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options: Any = None,
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memory_pool: Any = None,
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) -> ChunkedArrayStructArray: ...
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else:
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from pyarrow.compute import extract_regex
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from pyarrow.types import (
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is_dictionary, # noqa: F401
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is_duration,
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is_fixed_size_list,
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is_large_list,
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is_list,
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is_timestamp,
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)
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UNITS_DICT: Mapping[IntervalUnit, NativeIntervalUnit] = {
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"y": "year",
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"q": "quarter",
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"mo": "month",
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"d": "day",
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"h": "hour",
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"m": "minute",
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"s": "second",
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"ms": "millisecond",
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"us": "microsecond",
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"ns": "nanosecond",
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}
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lit = pa.scalar
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"""Alias for `pyarrow.scalar`."""
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def extract_py_scalar(value: Any, /) -> Any:
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from narwhals._arrow.series import maybe_extract_py_scalar
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return maybe_extract_py_scalar(value, return_py_scalar=True)
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def is_array_or_scalar(obj: Any) -> TypeIs[ArrayOrScalar]:
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"""Return True for any base `pyarrow` container."""
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return isinstance(obj, (pa.ChunkedArray, pa.Array, pa.Scalar))
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def chunked_array(
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arr: ArrayOrScalar | list[Iterable[Any]], dtype: pa.DataType | None = None, /
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) -> ChunkedArrayAny:
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if isinstance(arr, pa.ChunkedArray):
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return arr
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if isinstance(arr, list):
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return pa.chunked_array(arr, dtype)
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return pa.chunked_array([arr], dtype)
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def nulls_like(n: int, series: ArrowSeries) -> ArrayAny:
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"""Create a strongly-typed Array instance with all elements null.
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Uses the type of `series`, without upseting `mypy`.
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"""
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return pa.nulls(n, series.native.type)
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def zeros(n: int, /) -> pa.Int64Array:
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return pa.repeat(0, n)
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@lru_cache(maxsize=16)
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def native_to_narwhals_dtype(dtype: pa.DataType, version: Version) -> DType: # noqa: C901, PLR0912
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dtypes = version.dtypes
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if pa.types.is_int64(dtype):
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return dtypes.Int64()
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if pa.types.is_int32(dtype):
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return dtypes.Int32()
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if pa.types.is_int16(dtype):
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return dtypes.Int16()
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if pa.types.is_int8(dtype):
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return dtypes.Int8()
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if pa.types.is_uint64(dtype):
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return dtypes.UInt64()
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if pa.types.is_uint32(dtype):
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return dtypes.UInt32()
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if pa.types.is_uint16(dtype):
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return dtypes.UInt16()
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if pa.types.is_uint8(dtype):
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return dtypes.UInt8()
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if pa.types.is_boolean(dtype):
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return dtypes.Boolean()
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if pa.types.is_float64(dtype):
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return dtypes.Float64()
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if pa.types.is_float32(dtype):
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return dtypes.Float32()
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# bug in coverage? it shows `31->exit` (where `31` is currently the line number of
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# the next line), even though both when the if condition is true and false are covered
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if ( # pragma: no cover
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pa.types.is_string(dtype)
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or pa.types.is_large_string(dtype)
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or getattr(pa.types, "is_string_view", lambda _: False)(dtype)
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):
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return dtypes.String()
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if pa.types.is_date32(dtype):
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return dtypes.Date()
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if is_timestamp(dtype):
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return dtypes.Datetime(time_unit=dtype.unit, time_zone=dtype.tz)
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if is_duration(dtype):
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return dtypes.Duration(time_unit=dtype.unit)
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if pa.types.is_dictionary(dtype):
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return dtypes.Categorical()
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if pa.types.is_struct(dtype):
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return dtypes.Struct(
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[
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dtypes.Field(
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dtype.field(i).name,
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native_to_narwhals_dtype(dtype.field(i).type, version),
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)
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for i in range(dtype.num_fields)
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]
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)
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if is_list(dtype) or is_large_list(dtype):
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return dtypes.List(native_to_narwhals_dtype(dtype.value_type, version))
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if is_fixed_size_list(dtype):
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return dtypes.Array(
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native_to_narwhals_dtype(dtype.value_type, version), dtype.list_size
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)
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if pa.types.is_decimal(dtype):
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return dtypes.Decimal()
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if pa.types.is_time32(dtype) or pa.types.is_time64(dtype):
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return dtypes.Time()
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if pa.types.is_binary(dtype):
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return dtypes.Binary()
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return dtypes.Unknown() # pragma: no cover
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dtypes = Version.MAIN.dtypes
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NW_TO_PA_DTYPES: Mapping[type[DType], pa.DataType] = {
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dtypes.Float64: pa.float64(),
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dtypes.Float32: pa.float32(),
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dtypes.Binary: pa.binary(),
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dtypes.String: pa.string(),
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dtypes.Boolean: pa.bool_(),
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dtypes.Categorical: pa.dictionary(pa.uint32(), pa.string()),
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dtypes.Date: pa.date32(),
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dtypes.Time: pa.time64("ns"),
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dtypes.Int8: pa.int8(),
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dtypes.Int16: pa.int16(),
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dtypes.Int32: pa.int32(),
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dtypes.Int64: pa.int64(),
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dtypes.UInt8: pa.uint8(),
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dtypes.UInt16: pa.uint16(),
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dtypes.UInt32: pa.uint32(),
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dtypes.UInt64: pa.uint64(),
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}
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UNSUPPORTED_DTYPES = (dtypes.Decimal, dtypes.Object)
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def narwhals_to_native_dtype(dtype: IntoDType, version: Version) -> pa.DataType:
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dtypes = version.dtypes
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base_type = dtype.base_type()
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if pa_type := NW_TO_PA_DTYPES.get(base_type):
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return pa_type
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if isinstance_or_issubclass(dtype, dtypes.Datetime):
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unit = dtype.time_unit
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return pa.timestamp(unit, tz) if (tz := dtype.time_zone) else pa.timestamp(unit)
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if isinstance_or_issubclass(dtype, dtypes.Duration):
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return pa.duration(dtype.time_unit)
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if isinstance_or_issubclass(dtype, dtypes.List):
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return pa.list_(value_type=narwhals_to_native_dtype(dtype.inner, version=version))
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if isinstance_or_issubclass(dtype, dtypes.Struct):
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return pa.struct(
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[
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(field.name, narwhals_to_native_dtype(field.dtype, version=version))
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for field in dtype.fields
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]
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)
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if isinstance_or_issubclass(dtype, dtypes.Array): # pragma: no cover
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inner = narwhals_to_native_dtype(dtype.inner, version=version)
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list_size = dtype.size
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return pa.list_(inner, list_size=list_size)
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if issubclass(base_type, UNSUPPORTED_DTYPES):
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msg = f"Converting to {base_type.__name__} dtype is not supported for PyArrow."
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raise NotImplementedError(msg)
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msg = f"Unknown dtype: {dtype}" # pragma: no cover
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raise AssertionError(msg)
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def extract_native(
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lhs: ArrowSeries, rhs: ArrowSeries | PythonLiteral | ScalarAny
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) -> tuple[ChunkedArrayAny | ScalarAny, ChunkedArrayAny | ScalarAny]:
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"""Extract native objects in binary operation.
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If the comparison isn't supported, return `NotImplemented` so that the
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"right-hand-side" operation (e.g. `__radd__`) can be tried.
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If one of the two sides has a `_broadcast` flag, then extract the scalar
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underneath it so that PyArrow can do its own broadcasting.
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"""
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from narwhals._arrow.series import ArrowSeries
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if rhs is None: # pragma: no cover
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return lhs.native, lit(None, type=lhs._type)
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if isinstance(rhs, ArrowSeries):
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if lhs._broadcast and not rhs._broadcast:
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return lhs.native[0], rhs.native
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if rhs._broadcast:
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return lhs.native, rhs.native[0]
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return lhs.native, rhs.native
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if isinstance(rhs, list):
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msg = "Expected Series or scalar, got list."
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raise TypeError(msg)
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return lhs.native, rhs if isinstance(rhs, pa.Scalar) else lit(rhs)
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def floordiv_compat(left: ArrayOrScalar, right: ArrayOrScalar, /) -> Any:
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# The following lines are adapted from pandas' pyarrow implementation.
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# Ref: https://github.com/pandas-dev/pandas/blob/262fcfbffcee5c3116e86a951d8b693f90411e68/pandas/core/arrays/arrow/array.py#L124-L154
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if pa.types.is_integer(left.type) and pa.types.is_integer(right.type):
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divided = pc.divide_checked(left, right)
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# TODO @dangotbanned: Use a `TypeVar` in guards
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# Narrowing to a `Union` isn't interacting well with the rest of the stubs
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# https://github.com/zen-xu/pyarrow-stubs/pull/215
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if pa.types.is_signed_integer(divided.type):
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div_type = cast("pa._lib.Int64Type", divided.type)
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has_remainder = pc.not_equal(pc.multiply(divided, right), left)
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has_one_negative_operand = pc.less(
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pc.bit_wise_xor(left, right), lit(0, div_type)
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)
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result = pc.if_else(
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pc.and_(has_remainder, has_one_negative_operand),
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pc.subtract(divided, lit(1, div_type)),
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divided,
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)
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else:
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result = divided # pragma: no cover
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result = result.cast(left.type)
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else:
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divided = pc.divide(left, right)
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result = pc.floor(divided)
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return result
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def cast_for_truediv(
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arrow_array: ArrayOrScalarT1, pa_object: ArrayOrScalarT2
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) -> tuple[ArrayOrScalarT1, ArrayOrScalarT2]:
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# Lifted from:
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# https://github.com/pandas-dev/pandas/blob/262fcfbffcee5c3116e86a951d8b693f90411e68/pandas/core/arrays/arrow/array.py#L108-L122
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# Ensure int / int -> float mirroring Python/Numpy behavior
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# as pc.divide_checked(int, int) -> int
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if pa.types.is_integer(arrow_array.type) and pa.types.is_integer(pa_object.type):
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# GH: 56645. # noqa: ERA001
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# https://github.com/apache/arrow/issues/35563
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return arrow_array.cast(pa.float64(), safe=False), pa_object.cast(
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pa.float64(), safe=False
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)
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return arrow_array, pa_object
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# Regex for date, time, separator and timezone components
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DATE_RE = r"(?P<date>\d{1,4}[-/.]\d{1,2}[-/.]\d{1,4}|\d{8})"
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SEP_RE = r"(?P<sep>\s|T)"
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TIME_RE = r"(?P<time>\d{2}:\d{2}(?::\d{2})?|\d{6}?)" # \s*(?P<period>[AP]M)?)?
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HMS_RE = r"^(?P<hms>\d{2}:\d{2}:\d{2})$"
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HM_RE = r"^(?P<hm>\d{2}:\d{2})$"
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HMS_RE_NO_SEP = r"^(?P<hms_no_sep>\d{6})$"
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TZ_RE = r"(?P<tz>Z|[+-]\d{2}:?\d{2})" # Matches 'Z', '+02:00', '+0200', '+02', etc.
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FULL_RE = rf"{DATE_RE}{SEP_RE}?{TIME_RE}?{TZ_RE}?$"
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# Separate regexes for different date formats
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YMD_RE = r"^(?P<year>(?:[12][0-9])?[0-9]{2})(?P<sep1>[-/.])(?P<month>0[1-9]|1[0-2])(?P<sep2>[-/.])(?P<day>0[1-9]|[12][0-9]|3[01])$"
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DMY_RE = r"^(?P<day>0[1-9]|[12][0-9]|3[01])(?P<sep1>[-/.])(?P<month>0[1-9]|1[0-2])(?P<sep2>[-/.])(?P<year>(?:[12][0-9])?[0-9]{2})$"
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MDY_RE = r"^(?P<month>0[1-9]|1[0-2])(?P<sep1>[-/.])(?P<day>0[1-9]|[12][0-9]|3[01])(?P<sep2>[-/.])(?P<year>(?:[12][0-9])?[0-9]{2})$"
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YMD_RE_NO_SEP = r"^(?P<year>(?:[12][0-9])?[0-9]{2})(?P<month>0[1-9]|1[0-2])(?P<day>0[1-9]|[12][0-9]|3[01])$"
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DATE_FORMATS = (
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(YMD_RE_NO_SEP, "%Y%m%d"),
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(YMD_RE, "%Y-%m-%d"),
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(DMY_RE, "%d-%m-%Y"),
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(MDY_RE, "%m-%d-%Y"),
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)
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TIME_FORMATS = ((HMS_RE, "%H:%M:%S"), (HM_RE, "%H:%M"), (HMS_RE_NO_SEP, "%H%M%S"))
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def _extract_regex_concat_arrays(
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strings: ChunkedArrayAny,
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/,
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pattern: str,
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*,
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options: Any = None,
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memory_pool: Any = None,
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) -> pa.StructArray:
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r = pa.concat_arrays(
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extract_regex(strings, pattern, options=options, memory_pool=memory_pool).chunks
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)
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return cast("pa.StructArray", r)
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def parse_datetime_format(arr: ChunkedArrayAny) -> str:
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"""Try to infer datetime format from StringArray."""
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matches = _extract_regex_concat_arrays(arr.drop_null().slice(0, 10), pattern=FULL_RE)
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if not pc.all(matches.is_valid()).as_py():
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msg = (
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"Unable to infer datetime format, provided format is not supported. "
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"Please report a bug to https://github.com/narwhals-dev/narwhals/issues"
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)
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raise NotImplementedError(msg)
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separators = matches.field("sep")
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tz = matches.field("tz")
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# separators and time zones must be unique
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if pc.count(pc.unique(separators)).as_py() > 1:
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msg = "Found multiple separator values while inferring datetime format."
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raise ValueError(msg)
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if pc.count(pc.unique(tz)).as_py() > 1:
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msg = "Found multiple timezone values while inferring datetime format."
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raise ValueError(msg)
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date_value = _parse_date_format(cast("pc.StringArray", matches.field("date")))
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time_value = _parse_time_format(cast("pc.StringArray", matches.field("time")))
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sep_value = separators[0].as_py()
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tz_value = "%z" if tz[0].as_py() else ""
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return f"{date_value}{sep_value}{time_value}{tz_value}"
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def _parse_date_format(arr: pc.StringArray) -> str:
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for date_rgx, date_fmt in DATE_FORMATS:
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matches = pc.extract_regex(arr, pattern=date_rgx)
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if date_fmt == "%Y%m%d" and pc.all(matches.is_valid()).as_py():
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return date_fmt
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if (
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pc.all(matches.is_valid()).as_py()
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and pc.count(pc.unique(sep1 := matches.field("sep1"))).as_py() == 1
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and pc.count(pc.unique(sep2 := matches.field("sep2"))).as_py() == 1
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and (date_sep_value := sep1[0].as_py()) == sep2[0].as_py()
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):
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return date_fmt.replace("-", date_sep_value)
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msg = (
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"Unable to infer datetime format. "
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"Please report a bug to https://github.com/narwhals-dev/narwhals/issues"
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)
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raise ValueError(msg)
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def _parse_time_format(arr: pc.StringArray) -> str:
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for time_rgx, time_fmt in TIME_FORMATS:
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matches = pc.extract_regex(arr, pattern=time_rgx)
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if pc.all(matches.is_valid()).as_py():
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return time_fmt
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return ""
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def pad_series(
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series: ArrowSeries, *, window_size: int, center: bool
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) -> tuple[ArrowSeries, int]:
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"""Pad series with None values on the left and/or right side, depending on the specified parameters.
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Arguments:
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series: The input ArrowSeries to be padded.
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window_size: The desired size of the window.
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center: Specifies whether to center the padding or not.
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Returns:
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A tuple containing the padded ArrowSeries and the offset value.
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"""
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if not center:
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return series, 0
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offset_left = window_size // 2
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# subtract one if window_size is even
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offset_right = offset_left - (window_size % 2 == 0)
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pad_left = pa.array([None] * offset_left, type=series._type)
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pad_right = pa.array([None] * offset_right, type=series._type)
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concat = pa.concat_arrays([pad_left, *series.native.chunks, pad_right])
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return series._with_native(concat), offset_left + offset_right
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def cast_to_comparable_string_types(
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*chunked_arrays: ChunkedArrayAny, separator: str
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) -> tuple[Iterator[ChunkedArrayAny], ScalarAny]:
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# Ensure `chunked_arrays` are either all `string` or all `large_string`.
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dtype = (
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pa.string() # (PyArrow default)
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if not any(pa.types.is_large_string(ca.type) for ca in chunked_arrays)
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|
else pa.large_string()
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|
)
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|
return (ca.cast(dtype) for ca in chunked_arrays), lit(separator, dtype)
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class ArrowSeriesNamespace(EagerSeriesNamespace["ArrowSeries", "ChunkedArrayAny"]): ...
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