157 lines
6.3 KiB
Python
157 lines
6.3 KiB
Python
from __future__ import annotations
|
|
|
|
from types import ModuleType
|
|
from typing import TYPE_CHECKING, Literal, Union
|
|
|
|
from narwhals._typing_compat import TypeVar
|
|
from narwhals._utils import Implementation
|
|
|
|
if TYPE_CHECKING:
|
|
from typing_extensions import TypeAlias
|
|
|
|
# `str` aliases
|
|
_Polars: TypeAlias = Literal["polars"]
|
|
_Arrow: TypeAlias = Literal["pyarrow"]
|
|
_Dask: TypeAlias = Literal["dask"]
|
|
_DuckDB: TypeAlias = Literal["duckdb"]
|
|
_Pandas: TypeAlias = Literal["pandas"]
|
|
_Modin: TypeAlias = Literal["modin"]
|
|
_Cudf: TypeAlias = Literal["cudf"]
|
|
_PySpark: TypeAlias = Literal["pyspark"]
|
|
_SQLFrame: TypeAlias = Literal["sqlframe"]
|
|
_PySparkConnect: TypeAlias = Literal["pyspark[connect]"]
|
|
_Ibis: TypeAlias = Literal["ibis"]
|
|
_PandasLike: TypeAlias = Literal[_Pandas, _Cudf, _Modin]
|
|
_SparkLike: TypeAlias = Literal[_PySpark, _SQLFrame, _PySparkConnect]
|
|
_EagerOnly: TypeAlias = Literal[_PandasLike, _Arrow]
|
|
_EagerAllowed: TypeAlias = Literal[_Polars, _EagerOnly]
|
|
_LazyOnly: TypeAlias = Literal[_SparkLike, _Dask, _DuckDB, _Ibis]
|
|
_LazyAllowed: TypeAlias = Literal[_Polars, _LazyOnly]
|
|
|
|
# `Implementation` aliases
|
|
_PandasImpl: TypeAlias = Literal[Implementation.PANDAS]
|
|
_ModinImpl: TypeAlias = Literal[Implementation.MODIN]
|
|
_CudfImpl: TypeAlias = Literal[Implementation.CUDF]
|
|
_PySparkImpl: TypeAlias = Literal[Implementation.PYSPARK]
|
|
_SQLFrameImpl: TypeAlias = Literal[Implementation.SQLFRAME]
|
|
_PySparkConnectImpl: TypeAlias = Literal[Implementation.PYSPARK_CONNECT]
|
|
_PolarsImpl: TypeAlias = Literal[Implementation.POLARS]
|
|
_ArrowImpl: TypeAlias = Literal[Implementation.PYARROW]
|
|
_DaskImpl: TypeAlias = Literal[Implementation.DASK]
|
|
_DuckDBImpl: TypeAlias = Literal[Implementation.DUCKDB]
|
|
_IbisImpl: TypeAlias = Literal[Implementation.IBIS]
|
|
_PandasLikeImpl: TypeAlias = Literal[_PandasImpl, _CudfImpl, _ModinImpl]
|
|
_SparkLikeImpl: TypeAlias = Literal[_PySparkImpl, _SQLFrameImpl, _PySparkConnectImpl]
|
|
_EagerOnlyImpl: TypeAlias = Literal[_PandasLikeImpl, _ArrowImpl]
|
|
_EagerAllowedImpl: TypeAlias = Literal[_EagerOnlyImpl, _PolarsImpl] # noqa: PYI047
|
|
_LazyOnlyImpl: TypeAlias = Literal[_SparkLikeImpl, _DaskImpl, _DuckDBImpl, _IbisImpl]
|
|
_LazyAllowedImpl: TypeAlias = Literal[_LazyOnlyImpl, _PolarsImpl] # noqa: PYI047
|
|
|
|
# NOTE: Temporary aliases for gaps in `LazyFrame.collect`, `DataFrame.lazy`, see:
|
|
# - https://github.com/narwhals-dev/narwhals/pull/2971#discussion_r2277137003
|
|
# - https://github.com/narwhals-dev/narwhals/pull/3002#issuecomment-3194267667
|
|
_LazyFrameCollectImpl: TypeAlias = Literal[_PandasImpl, _PolarsImpl, _ArrowImpl] # noqa: PYI047
|
|
|
|
# `str | Implementation` aliases
|
|
Pandas: TypeAlias = Literal[_Pandas, _PandasImpl]
|
|
Cudf: TypeAlias = Literal[_Cudf, _CudfImpl]
|
|
Modin: TypeAlias = Literal[_Modin, _ModinImpl]
|
|
PySpark: TypeAlias = Literal[_PySpark, _PySparkImpl]
|
|
SQLFrame: TypeAlias = Literal[_SQLFrame, _SQLFrameImpl]
|
|
PySparkConnect: TypeAlias = Literal[_PySparkConnect, _PySparkConnectImpl]
|
|
Polars: TypeAlias = Literal[_Polars, _PolarsImpl]
|
|
Arrow: TypeAlias = Literal[_Arrow, _ArrowImpl]
|
|
Dask: TypeAlias = Literal[_Dask, _DaskImpl]
|
|
DuckDB: TypeAlias = Literal[_DuckDB, _DuckDBImpl]
|
|
Ibis: TypeAlias = Literal[_Ibis, _IbisImpl]
|
|
PandasLike: TypeAlias = Literal[_PandasLike, _PandasLikeImpl]
|
|
SparkLike: TypeAlias = Literal[_SparkLike, _SparkLikeImpl]
|
|
EagerOnly: TypeAlias = Literal[PandasLike, Arrow]
|
|
LazyOnly: TypeAlias = Literal[SparkLike, Dask, DuckDB, Ibis]
|
|
EagerAllowed: TypeAlias = Literal[EagerOnly, Polars]
|
|
"""A string name or [`narwhals.Implementation`][] of an eager backend.
|
|
|
|
- A string name, one of: `"cudf"`, `"modin"`, `"pandas"`, `"pyarrow"`, `"polars"`.
|
|
- An Implementation, such as: `Implementation.CUDF`, `Implementation.MODIN`, ...
|
|
"""
|
|
|
|
LazyAllowed: TypeAlias = Literal[LazyOnly, Polars]
|
|
"""A string name or [`narwhals.Implementation`][] of a lazy backend.
|
|
|
|
- A string name, such as: `"duckdb"`, `"ibis"`, `"dask"`, `"sqlframe"`, ...
|
|
- An Implementation, such as: `Implementation.POLARS`, `Implementation.PYSPARK`, ...
|
|
"""
|
|
|
|
BackendName: TypeAlias = Literal[_EagerAllowed, _LazyAllowed]
|
|
Backend: TypeAlias = Literal[EagerAllowed, LazyAllowed]
|
|
"""A string name or [`narwhals.Implementation`][] of a supported
|
|
backend (either eager or lazy).
|
|
|
|
- A string name, such as: `"duckdb"`, `"ibis"`, `"pandas"`, `"pyarrow"`, `"polars"`, ...
|
|
- An Implementation, such as: `Implementation.DASK`, `Implementation.PYSPARK`, ...
|
|
"""
|
|
|
|
BackendT = TypeVar("BackendT", bound=Backend)
|
|
IntoBackend: TypeAlias = Union[BackendT, ModuleType]
|
|
"""Anything that can be converted into a [`narwhals.Implementation`][].
|
|
|
|
`backend` can be specified in three ways.
|
|
|
|
Examples:
|
|
A string backend name, such as: `"pandas"`, `"pyarrow"`, `"modin"`, `"cudf"`
|
|
|
|
>>> import pandas as pd
|
|
>>> import narwhals as nw
|
|
>>>
|
|
>>> data = {"c": [5, 2], "d": [1, 4]}
|
|
>>> nw.DataFrame.from_dict(data, backend="pandas")
|
|
┌──────────────────┐
|
|
|Narwhals DataFrame|
|
|
|------------------|
|
|
| c d |
|
|
| 0 5 1 |
|
|
| 1 2 4 |
|
|
└──────────────────┘
|
|
|
|
An Implementation, such as: `Implementation.POLARS`, `Implementation.DUCKDB`, `Implementation.PYSPARK`
|
|
|
|
>>> import narwhals as nw
|
|
>>> nw.read_parquet("file.parquet", backend=nw.Implementation.PYARROW)
|
|
┌──────────────────┐
|
|
|Narwhals DataFrame|
|
|
|------------------|
|
|
| pyarrow.Table |
|
|
| a: int64 |
|
|
| b: int64 |
|
|
| ---- |
|
|
| a: [[1,2]] |
|
|
| b: [[4,5]] |
|
|
└──────────────────┘
|
|
|
|
A python module, such as `dask`, `ibis`, `sqlframe`
|
|
|
|
>>> import numpy as np
|
|
>>> import polars as pl
|
|
>>> import narwhals as nw
|
|
>>>
|
|
>>> arr = np.arange(5, 10)
|
|
>>> nw.Series.from_numpy("arr", arr, dtype=nw.Int8, backend=pl)
|
|
┌──────────────────┐
|
|
| Narwhals Series |
|
|
|------------------|
|
|
|shape: (5,) |
|
|
|Series: 'arr' [i8]|
|
|
|[ |
|
|
| 5 |
|
|
| 6 |
|
|
| 7 |
|
|
| 8 |
|
|
| 9 |
|
|
|] |
|
|
└──────────────────┘
|
|
"""
|
|
|
|
IntoBackendAny: TypeAlias = IntoBackend[Backend]
|
|
IntoBackendEager: TypeAlias = IntoBackend[EagerAllowed]
|
|
IntoBackendLazy: TypeAlias = IntoBackend[LazyAllowed]
|