DriverTrac/venv/lib/python3.12/site-packages/narwhals/_ibis/expr.py

385 lines
13 KiB
Python

from __future__ import annotations
import operator
from typing import TYPE_CHECKING, Any, Callable, TypeVar, cast
import ibis
from narwhals._ibis.expr_dt import IbisExprDateTimeNamespace
from narwhals._ibis.expr_list import IbisExprListNamespace
from narwhals._ibis.expr_str import IbisExprStringNamespace
from narwhals._ibis.expr_struct import IbisExprStructNamespace
from narwhals._ibis.utils import (
IntoColumn,
asc_nulls_first,
asc_nulls_last,
desc_nulls_first,
desc_nulls_last,
is_floating,
lit,
narwhals_to_native_dtype,
)
from narwhals._sql.expr import SQLExpr
from narwhals._utils import (
Implementation,
Version,
extend_bool,
no_default,
not_implemented,
zip_strict,
)
if TYPE_CHECKING:
from collections.abc import Iterator, Sequence
import ibis.expr.types as ir
from typing_extensions import Self
from narwhals._compliant import WindowInputs
from narwhals._compliant.typing import (
AliasNames,
EvalNames,
EvalSeries,
WindowFunction,
)
from narwhals._ibis.dataframe import IbisLazyFrame
from narwhals._ibis.namespace import IbisNamespace
from narwhals._typing import NoDefault
from narwhals._utils import _LimitedContext
from narwhals.typing import IntoDType, RankMethod, RollingInterpolationMethod
ExprT = TypeVar("ExprT", bound=ir.Value)
IbisWindowFunction = WindowFunction[IbisLazyFrame, ir.Value]
IbisWindowInputs = WindowInputs[ir.Value]
class IbisExpr(SQLExpr["IbisLazyFrame", "ir.Value"]):
_implementation = Implementation.IBIS
def __init__(
self,
call: EvalSeries[IbisLazyFrame, ir.Value],
window_function: IbisWindowFunction | None = None,
*,
evaluate_output_names: EvalNames[IbisLazyFrame],
alias_output_names: AliasNames | None,
version: Version,
implementation: Implementation = Implementation.IBIS,
) -> None:
self._call = call
self._evaluate_output_names = evaluate_output_names
self._alias_output_names = alias_output_names
self._version = version
self._window_function: IbisWindowFunction | None = window_function
@property
def window_function(self) -> IbisWindowFunction:
def default_window_func(
df: IbisLazyFrame, window_inputs: IbisWindowInputs
) -> Sequence[ir.Value]:
return [
expr.over(
ibis.window(
group_by=window_inputs.partition_by,
order_by=self._sort(*window_inputs.order_by),
)
)
for expr in self(df)
]
return self._window_function or default_window_func
def _window_expression(
self,
expr: ir.Value,
partition_by: Sequence[str | ir.Value] = (),
order_by: Sequence[IntoColumn] = (),
rows_start: int | None = None,
rows_end: int | None = None,
*,
descending: Sequence[bool] | None = None,
nulls_last: Sequence[bool] | None = None,
) -> ir.Value:
if rows_start is not None and rows_end is not None:
rows_between = {"preceding": -rows_start, "following": rows_end}
elif rows_end is not None:
rows_between = {"following": rows_end}
elif rows_start is not None: # pragma: no cover
rows_between = {"preceding": -rows_start}
else:
rows_between = {}
desc = descending or False
last = nulls_last or False
window = ibis.window(
group_by=partition_by,
order_by=self._sort(*order_by, descending=desc, nulls_last=last),
**rows_between,
)
return expr.over(window)
def _first(self, expr: ir.Value, *order_by: str) -> ir.Value:
return cast("ir.Column", expr).first(
order_by=self._sort(*order_by), include_null=True
)
def _last(self, expr: ir.Value, *order_by: str) -> ir.Value:
return cast("ir.Column", expr).last(
order_by=self._sort(*order_by), include_null=True
)
def __narwhals_namespace__(self) -> IbisNamespace: # pragma: no cover
from narwhals._ibis.namespace import IbisNamespace
return IbisNamespace(version=self._version)
def broadcast(self) -> Self:
# Ibis does its own broadcasting.
return self
@staticmethod
def _sort(
*cols: IntoColumn,
descending: Sequence[bool] | bool = False,
nulls_last: Sequence[bool] | bool = False,
) -> Iterator[ir.Column]:
n = len(cols)
descending = extend_bool(descending, n)
nulls_last = extend_bool(nulls_last, n)
mapping = {
(False, False): asc_nulls_first,
(False, True): asc_nulls_last,
(True, False): desc_nulls_first,
(True, True): desc_nulls_last,
}
for col, _desc, _nulls_last in zip_strict(cols, descending, nulls_last):
yield mapping[(_desc, _nulls_last)](col)
@classmethod
def from_column_names(
cls: type[Self],
evaluate_column_names: EvalNames[IbisLazyFrame],
/,
*,
context: _LimitedContext,
) -> Self:
def func(df: IbisLazyFrame) -> Sequence[ir.Column]:
return [df.native[name] for name in evaluate_column_names(df)]
return cls(
func,
evaluate_output_names=evaluate_column_names,
alias_output_names=None,
version=context._version,
)
@classmethod
def from_column_indices(cls, *column_indices: int, context: _LimitedContext) -> Self:
def func(df: IbisLazyFrame) -> Sequence[ir.Column]:
return [df.native[i] for i in column_indices]
return cls(
func,
evaluate_output_names=cls._eval_names_indices(column_indices),
alias_output_names=None,
version=context._version,
)
def _with_binary(self, op: Callable[..., ir.Value], other: Self) -> Self:
return self._with_callable(op, other=other)
def _with_elementwise(
self, op: Callable[..., ir.Value], /, **expressifiable_args: Self
) -> Self:
return self._with_callable(op, **expressifiable_args)
@classmethod
def _alias_native(cls, expr: ExprT, name: str, /) -> ExprT:
return cast("ExprT", expr.name(name))
def __invert__(self) -> Self:
invert = cast("Callable[..., ir.Value]", operator.invert)
return self._with_callable(invert)
def quantile(
self, quantile: float, interpolation: RollingInterpolationMethod
) -> Self:
if interpolation != "linear":
msg = "Only linear interpolation methods are supported for Ibis quantile."
raise NotImplementedError(msg)
return self._with_callable(lambda expr: expr.quantile(quantile))
def n_unique(self) -> Self:
return self._with_callable(
lambda expr: expr.nunique() + expr.isnull().any().cast("int8")
)
def len(self) -> Self:
def func(df: IbisLazyFrame) -> Sequence[ir.IntegerScalar]:
return [df.native.count() for _ in self._evaluate_output_names(df)]
return self.__class__(
func,
evaluate_output_names=self._evaluate_output_names,
alias_output_names=self._alias_output_names,
version=self._version,
)
def null_count(self) -> Self:
return self._with_callable(lambda expr: expr.isnull().sum())
def is_nan(self) -> Self:
def func(expr: ir.FloatingValue) -> ir.Value:
otherwise = expr.isnan() if is_floating(expr.type()) else False
return ibis.ifelse(expr.isnull(), None, otherwise)
return self._with_callable(func)
def is_finite(self) -> Self:
def func(expr: ir.IntegerValue | ir.FloatingValue) -> ir.Value:
if is_floating(expr.type()):
expr = cast("ir.FloatingValue", expr)
return ~(expr.isinf() | expr.isnan())
return ibis.ifelse(expr.isnull(), None, lit(True))
return self._with_callable(func)
def is_in(self, other: Sequence[Any]) -> Self:
return self._with_callable(lambda expr: expr.isin(other))
def fill_null(self, value: Self | None, strategy: Any, limit: int | None) -> Self:
# Ibis doesn't yet allow ignoring nulls in first/last with window functions, which makes forward/backward
# strategies inconsistent when there are nulls present: https://github.com/ibis-project/ibis/issues/9539
if strategy is not None:
msg = "`strategy` is not supported for the Ibis backend"
raise NotImplementedError(msg)
if limit is not None:
msg = "`limit` is not supported for the Ibis backend" # pragma: no cover
raise NotImplementedError(msg)
def _fill_null(expr: ir.Value, value: ir.Scalar) -> ir.Value:
return expr.fill_null(value)
assert value is not None # noqa: S101
return self._with_callable(_fill_null, value=value)
def cast(self, dtype: IntoDType) -> Self:
def _func(expr: ir.Column) -> ir.Value:
native_dtype = narwhals_to_native_dtype(dtype, self._version)
# ibis `cast` overloads do not include DataType, only literals
return expr.cast(native_dtype) # type: ignore[unused-ignore]
return self._with_callable(_func)
def is_unique(self) -> Self:
return self._with_callable(
lambda expr: expr.isnull().count().over(ibis.window(group_by=(expr))) == 1
)
def rank(self, method: RankMethod, *, descending: bool) -> Self:
def _rank(expr: ir.Column) -> ir.Value:
order_by = next(self._sort(expr, descending=descending, nulls_last=True))
window = ibis.window(order_by=order_by)
if method == "dense":
rank_ = order_by.dense_rank()
elif method == "ordinal":
rank_ = ibis.row_number().over(window)
else:
rank_ = order_by.rank()
# Ibis uses 0-based ranking. Add 1 to match polars 1-based rank.
rank_ = rank_ + lit(1)
# For "max" and "average", adjust using the count of rows in the partition.
if method == "max":
# Define a window partitioned by expr (i.e. each distinct value)
partition = ibis.window(group_by=[expr])
cnt = expr.count().over(partition)
rank_ = rank_ + cnt - lit(1)
elif method == "average":
partition = ibis.window(group_by=[expr])
cnt = expr.count().over(partition)
avg = cast("ir.NumericValue", (cnt - lit(1)) / lit(2.0))
rank_ = rank_ + avg
return ibis.cases((expr.notnull(), rank_))
def window_f(df: IbisLazyFrame, inputs: WindowInputs[ir.Value]) -> list[ir.Value]:
if inputs.order_by:
msg = "`rank` followed by `over` with `order_by` specified is not supported for Ibis backend."
raise NotImplementedError(msg)
return [
_rank(cast("ir.Column", expr)).over(
ibis.window(group_by=inputs.partition_by)
)
for expr in self(df)
]
return self._with_callable(_rank, window_f)
def replace_strict(
self,
default: IbisExpr | NoDefault,
old: Sequence[Any],
new: Sequence[Any],
*,
return_dtype: IntoDType | None,
) -> Self:
if default is no_default:
msg = "`replace_strict` requires an explicit value for `default` for ibis backend."
raise ValueError(msg)
ns = self.__narwhals_namespace__()
keys = list(old)
values = list(new)
mapping_expr = ibis.map(keys, values)
def func(df: IbisLazyFrame) -> list[ir.Value]:
default_col = df._evaluate_single_output_expr(default)
results = [
ns._when(expr.isin(keys), mapping_expr[expr], default_col)
for expr in self(df)
]
if return_dtype:
native_dtype = narwhals_to_native_dtype(return_dtype, self._version)
return [res.cast(native_dtype) for res in results] # pyright: ignore[reportArgumentType, reportCallIssue]
return results
return self.__class__(
func,
None,
evaluate_output_names=self._evaluate_output_names,
alias_output_names=self._alias_output_names,
version=self._version,
)
@property
def str(self) -> IbisExprStringNamespace:
return IbisExprStringNamespace(self)
@property
def dt(self) -> IbisExprDateTimeNamespace:
return IbisExprDateTimeNamespace(self)
@property
def list(self) -> IbisExprListNamespace:
return IbisExprListNamespace(self)
@property
def struct(self) -> IbisExprStructNamespace:
return IbisExprStructNamespace(self)
# NOTE: https://github.com/ibis-project/ibis/issues/10542
cum_prod = not_implemented()
# NOTE: https://github.com/ibis-project/ibis/issues/11176
skew = not_implemented()
kurtosis = not_implemented()
_count_star = not_implemented()
# Intentionally not implemented, as Ibis does its own expression rewriting.
_push_down_window_function = not_implemented()