Files
Buffteks-Website/streamlit-venv/lib/python3.10/site-packages/narwhals/_arrow/namespace.py
2025-01-10 21:40:35 +00:00

516 lines
18 KiB
Python
Executable File

from __future__ import annotations
from functools import reduce
from typing import TYPE_CHECKING
from typing import Any
from typing import Iterable
from typing import Literal
from typing import cast
from narwhals._arrow.dataframe import ArrowDataFrame
from narwhals._arrow.expr import ArrowExpr
from narwhals._arrow.selectors import ArrowSelectorNamespace
from narwhals._arrow.series import ArrowSeries
from narwhals._arrow.utils import broadcast_series
from narwhals._arrow.utils import horizontal_concat
from narwhals._arrow.utils import vertical_concat
from narwhals._expression_parsing import combine_root_names
from narwhals._expression_parsing import parse_into_exprs
from narwhals._expression_parsing import reduce_output_names
from narwhals.utils import Implementation
if TYPE_CHECKING:
from typing import Callable
from narwhals._arrow.typing import IntoArrowExpr
from narwhals.dtypes import DType
from narwhals.typing import DTypes
class ArrowNamespace:
def _create_expr_from_callable(
self,
func: Callable[[ArrowDataFrame], list[ArrowSeries]],
*,
depth: int,
function_name: str,
root_names: list[str] | None,
output_names: list[str] | None,
) -> ArrowExpr:
from narwhals._arrow.expr import ArrowExpr
return ArrowExpr(
func,
depth=depth,
function_name=function_name,
root_names=root_names,
output_names=output_names,
backend_version=self._backend_version,
dtypes=self._dtypes,
)
def _create_expr_from_series(self, series: ArrowSeries) -> ArrowExpr:
from narwhals._arrow.expr import ArrowExpr
return ArrowExpr(
lambda _df: [series],
depth=0,
function_name="series",
root_names=None,
output_names=None,
backend_version=self._backend_version,
dtypes=self._dtypes,
)
def _create_series_from_scalar(self, value: Any, series: ArrowSeries) -> ArrowSeries:
from narwhals._arrow.series import ArrowSeries
if self._backend_version < (13,) and hasattr(value, "as_py"): # pragma: no cover
value = value.as_py()
return ArrowSeries._from_iterable(
[value],
name=series.name,
backend_version=self._backend_version,
dtypes=self._dtypes,
)
def _create_compliant_series(self, value: Any) -> ArrowSeries:
import pyarrow as pa # ignore-banned-import()
from narwhals._arrow.series import ArrowSeries
return ArrowSeries(
native_series=pa.chunked_array([value]),
name="",
backend_version=self._backend_version,
dtypes=self._dtypes,
)
# --- not in spec ---
def __init__(self, *, backend_version: tuple[int, ...], dtypes: DTypes) -> None:
self._backend_version = backend_version
self._implementation = Implementation.PYARROW
self._dtypes = dtypes
# --- selection ---
def col(self, *column_names: str) -> ArrowExpr:
from narwhals._arrow.expr import ArrowExpr
return ArrowExpr.from_column_names(
*column_names, backend_version=self._backend_version, dtypes=self._dtypes
)
def nth(self, *column_indices: int) -> ArrowExpr:
from narwhals._arrow.expr import ArrowExpr
return ArrowExpr.from_column_indices(
*column_indices, backend_version=self._backend_version, dtypes=self._dtypes
)
def len(self) -> ArrowExpr:
# coverage bug? this is definitely hit
return ArrowExpr( # pragma: no cover
lambda df: [
ArrowSeries._from_iterable(
[len(df._native_frame)],
name="len",
backend_version=self._backend_version,
dtypes=self._dtypes,
)
],
depth=0,
function_name="len",
root_names=None,
output_names=["len"],
backend_version=self._backend_version,
dtypes=self._dtypes,
)
def all(self) -> ArrowExpr:
from narwhals._arrow.expr import ArrowExpr
from narwhals._arrow.series import ArrowSeries
return ArrowExpr(
lambda df: [
ArrowSeries(
df._native_frame[column_name],
name=column_name,
backend_version=df._backend_version,
dtypes=df._dtypes,
)
for column_name in df.columns
],
depth=0,
function_name="all",
root_names=None,
output_names=None,
backend_version=self._backend_version,
dtypes=self._dtypes,
)
def lit(self, value: Any, dtype: DType | None) -> ArrowExpr:
def _lit_arrow_series(_: ArrowDataFrame) -> ArrowSeries:
arrow_series = ArrowSeries._from_iterable(
data=[value],
name="lit",
backend_version=self._backend_version,
dtypes=self._dtypes,
)
if dtype:
return arrow_series.cast(dtype)
return arrow_series
return ArrowExpr(
lambda df: [_lit_arrow_series(df)],
depth=0,
function_name="lit",
root_names=None,
output_names=["lit"],
backend_version=self._backend_version,
dtypes=self._dtypes,
)
def all_horizontal(self, *exprs: IntoArrowExpr) -> ArrowExpr:
parsed_exprs = parse_into_exprs(*exprs, namespace=self)
def func(df: ArrowDataFrame) -> list[ArrowSeries]:
series = (s for _expr in parsed_exprs for s in _expr._call(df))
return [reduce(lambda x, y: x & y, series)]
return self._create_expr_from_callable(
func=func,
depth=max(x._depth for x in parsed_exprs) + 1,
function_name="all_horizontal",
root_names=combine_root_names(parsed_exprs),
output_names=reduce_output_names(parsed_exprs),
)
def any_horizontal(self, *exprs: IntoArrowExpr) -> ArrowExpr:
parsed_exprs = parse_into_exprs(*exprs, namespace=self)
def func(df: ArrowDataFrame) -> list[ArrowSeries]:
series = (s for _expr in parsed_exprs for s in _expr._call(df))
return [reduce(lambda x, y: x | y, series)]
return self._create_expr_from_callable(
func=func,
depth=max(x._depth for x in parsed_exprs) + 1,
function_name="any_horizontal",
root_names=combine_root_names(parsed_exprs),
output_names=reduce_output_names(parsed_exprs),
)
def sum_horizontal(self, *exprs: IntoArrowExpr) -> ArrowExpr:
parsed_exprs = parse_into_exprs(*exprs, namespace=self)
def func(df: ArrowDataFrame) -> list[ArrowSeries]:
series = (s.fill_null(0) for _expr in parsed_exprs for s in _expr._call(df))
return [reduce(lambda x, y: x + y, series)]
return self._create_expr_from_callable(
func=func,
depth=max(x._depth for x in parsed_exprs) + 1,
function_name="sum_horizontal",
root_names=combine_root_names(parsed_exprs),
output_names=reduce_output_names(parsed_exprs),
)
def mean_horizontal(self, *exprs: IntoArrowExpr) -> IntoArrowExpr:
parsed_exprs = parse_into_exprs(*exprs, namespace=self)
def func(df: ArrowDataFrame) -> list[ArrowSeries]:
series = (s.fill_null(0) for _expr in parsed_exprs for s in _expr._call(df))
non_na = (
1 - s.is_null().cast(self._dtypes.Int64())
for _expr in parsed_exprs
for s in _expr._call(df)
)
return [
reduce(lambda x, y: x + y, series) / reduce(lambda x, y: x + y, non_na)
]
return self._create_expr_from_callable(
func=func,
depth=max(x._depth for x in parsed_exprs) + 1,
function_name="mean_horizontal",
root_names=combine_root_names(parsed_exprs),
output_names=reduce_output_names(parsed_exprs),
)
def min_horizontal(self, *exprs: IntoArrowExpr) -> ArrowExpr:
import pyarrow.compute as pc # ignore-banned-import
parsed_exprs = parse_into_exprs(*exprs, namespace=self)
def func(df: ArrowDataFrame) -> list[ArrowSeries]:
init_series, *series = [s for _expr in parsed_exprs for s in _expr._call(df)]
return [
ArrowSeries(
native_series=reduce(
lambda x, y: pc.min_element_wise(x, y),
[s._native_series for s in series],
init_series._native_series,
),
name=init_series.name,
backend_version=self._backend_version,
dtypes=self._dtypes,
)
]
return self._create_expr_from_callable(
func=func,
depth=max(x._depth for x in parsed_exprs) + 1,
function_name="min_horizontal",
root_names=combine_root_names(parsed_exprs),
output_names=reduce_output_names(parsed_exprs),
)
def max_horizontal(self, *exprs: IntoArrowExpr) -> ArrowExpr:
import pyarrow.compute as pc # ignore-banned-import
parsed_exprs = parse_into_exprs(*exprs, namespace=self)
def func(df: ArrowDataFrame) -> list[ArrowSeries]:
init_series, *series = [s for _expr in parsed_exprs for s in _expr._call(df)]
return [
ArrowSeries(
native_series=reduce(
lambda x, y: pc.max_element_wise(x, y),
[s._native_series for s in series],
init_series._native_series,
),
name=init_series.name,
backend_version=self._backend_version,
dtypes=self._dtypes,
)
]
return self._create_expr_from_callable(
func=func,
depth=max(x._depth for x in parsed_exprs) + 1,
function_name="max_horizontal",
root_names=combine_root_names(parsed_exprs),
output_names=reduce_output_names(parsed_exprs),
)
def concat(
self,
items: Iterable[ArrowDataFrame],
*,
how: Literal["horizontal", "vertical"],
) -> ArrowDataFrame:
dfs: list[Any] = [item._native_frame for item in items]
if how == "horizontal":
return ArrowDataFrame(
horizontal_concat(dfs),
backend_version=self._backend_version,
dtypes=self._dtypes,
)
if how == "vertical":
return ArrowDataFrame(
vertical_concat(dfs),
backend_version=self._backend_version,
dtypes=self._dtypes,
)
raise NotImplementedError
def sum(self, *column_names: str) -> ArrowExpr:
return ArrowExpr.from_column_names(
*column_names, backend_version=self._backend_version, dtypes=self._dtypes
).sum()
def mean(self, *column_names: str) -> ArrowExpr:
return ArrowExpr.from_column_names(
*column_names, backend_version=self._backend_version, dtypes=self._dtypes
).mean()
def max(self, *column_names: str) -> ArrowExpr:
return ArrowExpr.from_column_names(
*column_names, backend_version=self._backend_version, dtypes=self._dtypes
).max()
def min(self, *column_names: str) -> ArrowExpr:
return ArrowExpr.from_column_names(
*column_names, backend_version=self._backend_version, dtypes=self._dtypes
).min()
@property
def selectors(self) -> ArrowSelectorNamespace:
return ArrowSelectorNamespace(
backend_version=self._backend_version, dtypes=self._dtypes
)
def when(
self,
*predicates: IntoArrowExpr,
) -> ArrowWhen:
plx = self.__class__(backend_version=self._backend_version, dtypes=self._dtypes)
if predicates:
condition = plx.all_horizontal(*predicates)
else:
msg = "at least one predicate needs to be provided"
raise TypeError(msg)
return ArrowWhen(condition, self._backend_version, dtypes=self._dtypes)
def concat_str(
self,
exprs: Iterable[IntoArrowExpr],
*more_exprs: IntoArrowExpr,
separator: str = "",
ignore_nulls: bool = False,
) -> ArrowExpr:
import pyarrow.compute as pc # ignore-banned-import
parsed_exprs: list[ArrowExpr] = [
*parse_into_exprs(*exprs, namespace=self),
*parse_into_exprs(*more_exprs, namespace=self),
]
def func(df: ArrowDataFrame) -> list[ArrowSeries]:
series = (
s._native_series
for _expr in parsed_exprs
for s in _expr.cast(self._dtypes.String())._call(df)
)
null_handling = "skip" if ignore_nulls else "emit_null"
result_series = pc.binary_join_element_wise(
*series, separator, null_handling=null_handling
)
return [
ArrowSeries(
native_series=result_series,
name="",
backend_version=self._backend_version,
dtypes=self._dtypes,
)
]
return self._create_expr_from_callable(
func=func,
depth=max(x._depth for x in parsed_exprs) + 1,
function_name="concat_str",
root_names=combine_root_names(parsed_exprs),
output_names=reduce_output_names(parsed_exprs),
)
class ArrowWhen:
def __init__(
self,
condition: ArrowExpr,
backend_version: tuple[int, ...],
then_value: Any = None,
otherwise_value: Any = None,
*,
dtypes: DTypes,
) -> None:
self._backend_version = backend_version
self._condition = condition
self._then_value = then_value
self._otherwise_value = otherwise_value
self._dtypes = dtypes
def __call__(self, df: ArrowDataFrame) -> list[ArrowSeries]:
import pyarrow as pa # ignore-banned-import
import pyarrow.compute as pc # ignore-banned-import
from narwhals._arrow.namespace import ArrowNamespace
from narwhals._expression_parsing import parse_into_expr
plx = ArrowNamespace(backend_version=self._backend_version, dtypes=self._dtypes)
condition = parse_into_expr(self._condition, namespace=plx)._call(df)[0] # type: ignore[arg-type]
try:
value_series = parse_into_expr(self._then_value, namespace=plx)._call(df)[0] # type: ignore[arg-type]
except TypeError:
# `self._otherwise_value` is a scalar and can't be converted to an expression
value_series = condition.__class__._from_iterable( # type: ignore[call-arg]
[self._then_value] * len(condition),
name="literal",
backend_version=self._backend_version,
dtypes=self._dtypes,
)
value_series = cast(ArrowSeries, value_series)
value_series_native = value_series._native_series
condition_native = condition._native_series.combine_chunks()
if self._otherwise_value is None:
otherwise_native = pa.array(
[None] * len(condition_native), type=value_series_native.type
)
return [
value_series._from_native_series(
pc.if_else(condition_native, value_series_native, otherwise_native)
)
]
try:
otherwise_series = parse_into_expr(
self._otherwise_value, namespace=plx
)._call(df)[0] # type: ignore[arg-type]
except TypeError:
# `self._otherwise_value` is a scalar and can't be converted to an expression.
# Remark that string values _are_ converted into expressions!
return [
value_series._from_native_series(
pc.if_else(
condition_native, value_series_native, self._otherwise_value
)
)
]
else:
otherwise_series = cast(ArrowSeries, otherwise_series)
condition = cast(ArrowSeries, condition)
condition_native, otherwise_native = broadcast_series(
[condition, otherwise_series]
)
return [
value_series._from_native_series(
pc.if_else(condition_native, value_series_native, otherwise_native)
)
]
def then(self, value: ArrowExpr | ArrowSeries | Any) -> ArrowThen:
self._then_value = value
return ArrowThen(
self,
depth=0,
function_name="whenthen",
root_names=None,
output_names=None,
backend_version=self._backend_version,
dtypes=self._dtypes,
)
class ArrowThen(ArrowExpr):
def __init__(
self,
call: ArrowWhen,
*,
depth: int,
function_name: str,
root_names: list[str] | None,
output_names: list[str] | None,
backend_version: tuple[int, ...],
dtypes: DTypes,
) -> None:
self._backend_version = backend_version
self._dtypes = dtypes
self._call = call
self._depth = depth
self._function_name = function_name
self._root_names = root_names
self._output_names = output_names
def otherwise(self, value: ArrowExpr | ArrowSeries | Any) -> ArrowExpr:
# type ignore because we are setting the `_call` attribute to a
# callable object of type `PandasWhen`, base class has the attribute as
# only a `Callable`
self._call._otherwise_value = value # type: ignore[attr-defined]
self._function_name = "whenotherwise"
return self