242 lines
8.4 KiB
Python
242 lines
8.4 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, TypeVar, overload
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import polars as pl
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from narwhals._utils import (
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Implementation,
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Version,
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_DeferredIterable,
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isinstance_or_issubclass,
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)
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from narwhals.exceptions import (
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ColumnNotFoundError,
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ComputeError,
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DuplicateError,
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InvalidOperationError,
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NarwhalsError,
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ShapeError,
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)
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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 TypeIs
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from narwhals._utils import _StoresNative
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from narwhals.dtypes import DType
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from narwhals.typing import IntoDType
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T = TypeVar("T")
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NativeT = TypeVar(
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"NativeT", bound="pl.DataFrame | pl.LazyFrame | pl.Series | pl.Expr"
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)
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BACKEND_VERSION = Implementation.POLARS._backend_version()
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"""Static backend version for `polars`."""
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@overload
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def extract_native(obj: _StoresNative[NativeT]) -> NativeT: ...
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@overload
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def extract_native(obj: T) -> T: ...
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def extract_native(obj: _StoresNative[NativeT] | T) -> NativeT | T:
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return obj.native if _is_compliant_polars(obj) else obj
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def _is_compliant_polars(
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obj: _StoresNative[NativeT] | Any,
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) -> TypeIs[_StoresNative[NativeT]]:
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from narwhals._polars.dataframe import PolarsDataFrame, PolarsLazyFrame
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from narwhals._polars.expr import PolarsExpr
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from narwhals._polars.series import PolarsSeries
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return isinstance(obj, (PolarsDataFrame, PolarsLazyFrame, PolarsSeries, PolarsExpr))
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def extract_args_kwargs(
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args: Iterable[Any], kwds: Mapping[str, Any], /
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) -> tuple[Iterator[Any], dict[str, Any]]:
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it_args = (extract_native(arg) for arg in args)
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return it_args, {k: extract_native(v) for k, v in kwds.items()}
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@lru_cache(maxsize=16)
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def native_to_narwhals_dtype( # noqa: C901, PLR0912
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dtype: pl.DataType, version: Version
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) -> DType:
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dtypes = version.dtypes
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if dtype == pl.Float64:
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return dtypes.Float64()
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if dtype == pl.Float32:
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return dtypes.Float32()
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if hasattr(pl, "Int128") and dtype == pl.Int128: # pragma: no cover
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# Not available for Polars pre 1.8.0
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return dtypes.Int128()
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if dtype == pl.Int64:
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return dtypes.Int64()
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if dtype == pl.Int32:
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return dtypes.Int32()
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if dtype == pl.Int16:
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return dtypes.Int16()
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if dtype == pl.Int8:
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return dtypes.Int8()
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if hasattr(pl, "UInt128") and dtype == pl.UInt128: # pragma: no cover
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# Not available for Polars pre 1.8.0
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return dtypes.UInt128()
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if dtype == pl.UInt64:
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return dtypes.UInt64()
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if dtype == pl.UInt32:
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return dtypes.UInt32()
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if dtype == pl.UInt16:
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return dtypes.UInt16()
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if dtype == pl.UInt8:
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return dtypes.UInt8()
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if dtype == pl.String:
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return dtypes.String()
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if dtype == pl.Boolean:
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return dtypes.Boolean()
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if dtype == pl.Object:
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return dtypes.Object()
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if dtype == pl.Categorical:
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return dtypes.Categorical()
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if isinstance_or_issubclass(dtype, pl.Enum):
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if version is Version.V1:
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return dtypes.Enum() # type: ignore[call-arg]
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categories = _DeferredIterable(dtype.categories.to_list)
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return dtypes.Enum(categories)
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if dtype == pl.Date:
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return dtypes.Date()
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if isinstance_or_issubclass(dtype, pl.Datetime):
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return (
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dtypes.Datetime()
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if dtype is pl.Datetime
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else dtypes.Datetime(dtype.time_unit, dtype.time_zone)
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)
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if isinstance_or_issubclass(dtype, pl.Duration):
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return (
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dtypes.Duration()
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if dtype is pl.Duration
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else dtypes.Duration(dtype.time_unit)
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)
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if isinstance_or_issubclass(dtype, pl.Struct):
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fields = [
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dtypes.Field(name, native_to_narwhals_dtype(tp, version))
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for name, tp in dtype
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]
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return dtypes.Struct(fields)
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if isinstance_or_issubclass(dtype, pl.List):
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return dtypes.List(native_to_narwhals_dtype(dtype.inner, version))
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if isinstance_or_issubclass(dtype, pl.Array):
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outer_shape = dtype.width if BACKEND_VERSION < (0, 20, 30) else dtype.size
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return dtypes.Array(native_to_narwhals_dtype(dtype.inner, version), outer_shape)
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if dtype == pl.Decimal:
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return dtypes.Decimal()
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if dtype == pl.Time:
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return dtypes.Time()
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if dtype == pl.Binary:
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return dtypes.Binary()
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return dtypes.Unknown()
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def narwhals_to_native_dtype( # noqa: C901, PLR0912
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dtype: IntoDType, version: Version
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) -> pl.DataType:
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dtypes = version.dtypes
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if dtype == dtypes.Float64:
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return pl.Float64()
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if dtype == dtypes.Float32:
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return pl.Float32()
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if dtype == dtypes.Int128 and hasattr(pl, "Int128"):
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# Not available for Polars pre 1.8.0
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return pl.Int128()
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if dtype == dtypes.Int64:
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return pl.Int64()
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if dtype == dtypes.Int32:
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return pl.Int32()
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if dtype == dtypes.Int16:
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return pl.Int16()
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if dtype == dtypes.Int8:
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return pl.Int8()
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if dtype == dtypes.UInt64:
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return pl.UInt64()
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if dtype == dtypes.UInt32:
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return pl.UInt32()
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if dtype == dtypes.UInt16:
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return pl.UInt16()
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if dtype == dtypes.UInt8:
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return pl.UInt8()
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if dtype == dtypes.String:
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return pl.String()
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if dtype == dtypes.Boolean:
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return pl.Boolean()
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if dtype == dtypes.Object: # pragma: no cover
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return pl.Object()
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if dtype == dtypes.Categorical:
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return pl.Categorical()
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if isinstance_or_issubclass(dtype, dtypes.Enum):
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if version is Version.V1:
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msg = "Converting to Enum is not supported in narwhals.stable.v1"
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raise NotImplementedError(msg)
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if isinstance(dtype, dtypes.Enum):
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return pl.Enum(dtype.categories)
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msg = "Can not cast / initialize Enum without categories present"
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raise ValueError(msg)
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if dtype == dtypes.Date:
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return pl.Date()
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if dtype == dtypes.Time:
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return pl.Time()
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if dtype == dtypes.Binary:
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return pl.Binary()
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if dtype == dtypes.Decimal:
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msg = "Casting to Decimal is not supported yet."
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raise NotImplementedError(msg)
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if isinstance_or_issubclass(dtype, dtypes.Datetime):
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return pl.Datetime(dtype.time_unit, dtype.time_zone) # type: ignore[arg-type]
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if isinstance_or_issubclass(dtype, dtypes.Duration):
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return pl.Duration(dtype.time_unit) # type: ignore[arg-type]
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if isinstance_or_issubclass(dtype, dtypes.List):
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return pl.List(narwhals_to_native_dtype(dtype.inner, version))
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if isinstance_or_issubclass(dtype, dtypes.Struct):
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fields = [
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pl.Field(field.name, narwhals_to_native_dtype(field.dtype, version))
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for field in dtype.fields
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]
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return pl.Struct(fields)
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if isinstance_or_issubclass(dtype, dtypes.Array): # pragma: no cover
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size = dtype.size
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kwargs = {"width": size} if BACKEND_VERSION < (0, 20, 30) else {"shape": size}
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return pl.Array(narwhals_to_native_dtype(dtype.inner, version), **kwargs)
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return pl.Unknown() # pragma: no cover
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def _is_polars_exception(exception: Exception) -> bool:
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if BACKEND_VERSION >= (1,):
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# Old versions of Polars didn't have PolarsError.
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return isinstance(exception, pl.exceptions.PolarsError)
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# Last attempt, for old Polars versions.
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return "polars.exceptions" in str(type(exception)) # pragma: no cover
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def _is_cudf_exception(exception: Exception) -> bool:
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# These exceptions are raised when running polars on GPUs via cuDF
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return str(exception).startswith("CUDF failure")
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def catch_polars_exception(exception: Exception) -> NarwhalsError | Exception:
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if isinstance(exception, pl.exceptions.ColumnNotFoundError):
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return ColumnNotFoundError(str(exception))
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elif isinstance(exception, pl.exceptions.ShapeError):
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return ShapeError(str(exception))
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elif isinstance(exception, pl.exceptions.InvalidOperationError):
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return InvalidOperationError(str(exception))
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elif isinstance(exception, pl.exceptions.DuplicateError):
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return DuplicateError(str(exception))
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elif isinstance(exception, pl.exceptions.ComputeError):
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return ComputeError(str(exception))
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if _is_polars_exception(exception) or _is_cudf_exception(exception):
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return NarwhalsError(str(exception)) # pragma: no cover
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# Just return exception as-is.
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return exception
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