282 lines
10 KiB
Python
282 lines
10 KiB
Python
from __future__ import annotations
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import operator
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from typing import TYPE_CHECKING, Any, Literal, cast, overload
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import polars as pl
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from narwhals._expression_parsing import is_expr, is_series
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from narwhals._polars.expr import PolarsExpr
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from narwhals._polars.series import PolarsSeries
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from narwhals._polars.utils import extract_args_kwargs, narwhals_to_native_dtype
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from narwhals._utils import Implementation, requires, zip_strict
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from narwhals.dependencies import is_numpy_array_2d
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from narwhals.dtypes import DType
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if TYPE_CHECKING:
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from collections.abc import Iterable, Sequence
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from datetime import timezone
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from narwhals._compliant import CompliantSelectorNamespace, CompliantWhen
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from narwhals._polars.dataframe import Method, PolarsDataFrame, PolarsLazyFrame
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from narwhals._polars.typing import FrameT
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from narwhals._utils import Version, _LimitedContext
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from narwhals.expr import Expr
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from narwhals.series import Series
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from narwhals.typing import (
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Into1DArray,
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IntoDType,
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IntoSchema,
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NonNestedLiteral,
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TimeUnit,
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_1DArray,
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_2DArray,
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)
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class PolarsNamespace:
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all: Method[PolarsExpr]
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coalesce: Method[PolarsExpr]
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col: Method[PolarsExpr]
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exclude: Method[PolarsExpr]
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sum_horizontal: Method[PolarsExpr]
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min_horizontal: Method[PolarsExpr]
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max_horizontal: Method[PolarsExpr]
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when: Method[CompliantWhen[PolarsDataFrame, PolarsSeries, PolarsExpr]]
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_implementation: Implementation = Implementation.POLARS
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_version: Version
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@property
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def _backend_version(self) -> tuple[int, ...]:
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return self._implementation._backend_version()
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def __init__(self, *, version: Version) -> None:
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self._version = version
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def __getattr__(self, attr: str) -> Any:
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def func(*args: Any, **kwargs: Any) -> Any:
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pos, kwds = extract_args_kwargs(args, kwargs)
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return self._expr(getattr(pl, attr)(*pos, **kwds), version=self._version)
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return func
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@property
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def _dataframe(self) -> type[PolarsDataFrame]:
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from narwhals._polars.dataframe import PolarsDataFrame
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return PolarsDataFrame
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@property
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def _lazyframe(self) -> type[PolarsLazyFrame]:
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from narwhals._polars.dataframe import PolarsLazyFrame
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return PolarsLazyFrame
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@property
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def _expr(self) -> type[PolarsExpr]:
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return PolarsExpr
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@property
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def _series(self) -> type[PolarsSeries]:
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return PolarsSeries
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def parse_into_expr(
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self,
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data: Expr | NonNestedLiteral | Series[pl.Series] | _1DArray,
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/,
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*,
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str_as_lit: bool,
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) -> PolarsExpr | None:
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if data is None:
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# NOTE: To avoid `pl.lit(None)` failing this `None` check
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# https://github.com/pola-rs/polars/blob/58dd8e5770f16a9bef9009a1c05f00e15a5263c7/py-polars/polars/expr/expr.py#L2870-L2872
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return data
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if is_expr(data):
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expr = data._to_compliant_expr(self)
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assert isinstance(expr, self._expr) # noqa: S101
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return expr
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if isinstance(data, str) and not str_as_lit:
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return self.col(data)
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return self.lit(data.to_native() if is_series(data) else data, None)
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@overload
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def from_native(self, data: pl.DataFrame, /) -> PolarsDataFrame: ...
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@overload
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def from_native(self, data: pl.LazyFrame, /) -> PolarsLazyFrame: ...
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@overload
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def from_native(self, data: pl.Series, /) -> PolarsSeries: ...
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def from_native(
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self, data: pl.DataFrame | pl.LazyFrame | pl.Series | Any, /
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) -> PolarsDataFrame | PolarsLazyFrame | PolarsSeries:
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if self._dataframe._is_native(data):
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return self._dataframe.from_native(data, context=self)
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if self._series._is_native(data):
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return self._series.from_native(data, context=self)
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if self._lazyframe._is_native(data):
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return self._lazyframe.from_native(data, context=self)
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msg = f"Unsupported type: {type(data).__name__!r}" # pragma: no cover
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raise TypeError(msg) # pragma: no cover
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@overload
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def from_numpy(self, data: Into1DArray, /, schema: None = ...) -> PolarsSeries: ...
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@overload
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def from_numpy(
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self, data: _2DArray, /, schema: IntoSchema | Sequence[str] | None
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) -> PolarsDataFrame: ...
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def from_numpy(
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self,
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data: Into1DArray | _2DArray,
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/,
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schema: IntoSchema | Sequence[str] | None = None,
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) -> PolarsDataFrame | PolarsSeries:
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if is_numpy_array_2d(data):
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return self._dataframe.from_numpy(data, schema=schema, context=self)
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return self._series.from_numpy(data, context=self) # pragma: no cover
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@requires.backend_version(
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(1, 0, 0), "Please use `col` for columns selection instead."
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)
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def nth(self, *indices: int) -> PolarsExpr:
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return self._expr(pl.nth(*indices), version=self._version)
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def len(self) -> PolarsExpr:
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if self._backend_version < (0, 20, 5):
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return self._expr(pl.count().alias("len"), self._version)
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return self._expr(pl.len(), self._version)
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def all_horizontal(self, *exprs: PolarsExpr, ignore_nulls: bool) -> PolarsExpr:
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it = (expr.fill_null(True) for expr in exprs) if ignore_nulls else iter(exprs)
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return self._expr(pl.all_horizontal(*(expr.native for expr in it)), self._version)
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def any_horizontal(self, *exprs: PolarsExpr, ignore_nulls: bool) -> PolarsExpr:
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it = (expr.fill_null(False) for expr in exprs) if ignore_nulls else iter(exprs)
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return self._expr(pl.any_horizontal(*(expr.native for expr in it)), self._version)
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def concat(
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self,
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items: Iterable[FrameT],
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*,
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how: Literal["vertical", "horizontal", "diagonal"],
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) -> PolarsDataFrame | PolarsLazyFrame:
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result = pl.concat((item.native for item in items), how=how)
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if isinstance(result, pl.DataFrame):
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return self._dataframe(result, version=self._version)
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return self._lazyframe.from_native(result, context=self)
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def lit(self, value: Any, dtype: IntoDType | None) -> PolarsExpr:
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if dtype is not None:
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return self._expr(
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pl.lit(value, dtype=narwhals_to_native_dtype(dtype, self._version)),
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version=self._version,
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)
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return self._expr(pl.lit(value), version=self._version)
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def mean_horizontal(self, *exprs: PolarsExpr) -> PolarsExpr:
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if self._backend_version < (0, 20, 8):
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return self._expr(
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pl.sum_horizontal(e._native_expr for e in exprs)
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/ pl.sum_horizontal(1 - e.is_null()._native_expr for e in exprs),
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version=self._version,
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)
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return self._expr(
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pl.mean_horizontal(e._native_expr for e in exprs), version=self._version
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)
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def concat_str(
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self, *exprs: PolarsExpr, separator: str, ignore_nulls: bool
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) -> PolarsExpr:
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pl_exprs: list[pl.Expr] = [expr._native_expr for expr in exprs]
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if self._backend_version < (0, 20, 6):
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null_mask = [expr.is_null() for expr in pl_exprs]
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sep = pl.lit(separator)
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if not ignore_nulls:
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null_mask_result = pl.any_horizontal(*null_mask)
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output_expr = pl.reduce(
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lambda x, y: x.cast(pl.String()) + sep + y.cast(pl.String()), # type: ignore[arg-type,return-value]
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pl_exprs,
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)
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result = pl.when(~null_mask_result).then(output_expr)
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else:
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init_value, *values = [
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pl.when(nm).then(pl.lit("")).otherwise(expr.cast(pl.String()))
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for expr, nm in zip_strict(pl_exprs, null_mask)
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]
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separators = [
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pl.when(~nm).then(sep).otherwise(pl.lit("")) for nm in null_mask[:-1]
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]
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result = pl.fold( # type: ignore[assignment]
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acc=init_value,
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function=operator.add,
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exprs=[s + v for s, v in zip_strict(separators, values)],
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)
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return self._expr(result, version=self._version)
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return self._expr(
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pl.concat_str(pl_exprs, separator=separator, ignore_nulls=ignore_nulls),
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version=self._version,
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)
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# NOTE: Implementation is too different to annotate correctly (vs other `*SelectorNamespace`)
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# 1. Others have lots of private stuff for code reuse
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# i. None of that is useful here
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# 2. We don't have a `PolarsSelector` abstraction, and just use `PolarsExpr`
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@property
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def selectors(self) -> CompliantSelectorNamespace[PolarsDataFrame, PolarsSeries]:
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return cast(
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"CompliantSelectorNamespace[PolarsDataFrame, PolarsSeries]",
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PolarsSelectorNamespace(self),
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)
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class PolarsSelectorNamespace:
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_implementation = Implementation.POLARS
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def __init__(self, context: _LimitedContext, /) -> None:
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self._version = context._version
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def by_dtype(self, dtypes: Iterable[DType]) -> PolarsExpr:
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native_dtypes = [
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narwhals_to_native_dtype(dtype, self._version).__class__
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if isinstance(dtype, type) and issubclass(dtype, DType)
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else narwhals_to_native_dtype(dtype, self._version)
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for dtype in dtypes
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]
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return PolarsExpr(pl.selectors.by_dtype(native_dtypes), version=self._version)
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def matches(self, pattern: str) -> PolarsExpr:
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return PolarsExpr(pl.selectors.matches(pattern=pattern), version=self._version)
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def numeric(self) -> PolarsExpr:
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return PolarsExpr(pl.selectors.numeric(), version=self._version)
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def boolean(self) -> PolarsExpr:
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return PolarsExpr(pl.selectors.boolean(), version=self._version)
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def string(self) -> PolarsExpr:
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return PolarsExpr(pl.selectors.string(), version=self._version)
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def categorical(self) -> PolarsExpr:
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return PolarsExpr(pl.selectors.categorical(), version=self._version)
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def all(self) -> PolarsExpr:
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return PolarsExpr(pl.selectors.all(), version=self._version)
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def datetime(
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self,
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time_unit: TimeUnit | Iterable[TimeUnit] | None,
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time_zone: str | timezone | Iterable[str | timezone | None] | None,
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) -> PolarsExpr:
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return PolarsExpr(
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pl.selectors.datetime(time_unit=time_unit, time_zone=time_zone), # type: ignore[arg-type]
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version=self._version,
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)
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