# pandas / Polars / etc. : if a user passes a dataframe from one of these # libraries, it means they must already have imported the given module. # So, we can just check sys.modules. from __future__ import annotations import sys from typing import TYPE_CHECKING from typing import Any if TYPE_CHECKING: import cudf import dask.dataframe as dd import duckdb import ibis import modin.pandas as mpd import numpy as np import pandas as pd import polars as pl import pyarrow as pa import pyspark.sql as pyspark_sql from typing_extensions import TypeGuard from typing_extensions import TypeIs from narwhals._arrow.typing import ArrowChunkedArray from narwhals._spark_like.dataframe import SQLFrameDataFrame from narwhals.dataframe import DataFrame from narwhals.dataframe import LazyFrame from narwhals.series import Series from narwhals.typing import DataFrameT from narwhals.typing import FrameT from narwhals.typing import IntoDataFrameT from narwhals.typing import IntoSeriesT from narwhals.typing import _1DArray from narwhals.typing import _2DArray from narwhals.typing import _NDArray from narwhals.typing import _ShapeT # We silently allow these but - given that they claim # to be drop-in replacements for pandas - testing is # their responsibility. IMPORT_HOOKS = frozenset(["fireducks"]) def get_polars() -> Any: """Get Polars module (if already imported - else return None).""" return sys.modules.get("polars", None) def get_pandas() -> Any: """Get pandas module (if already imported - else return None).""" return sys.modules.get("pandas", None) def get_modin() -> Any: # pragma: no cover """Get modin.pandas module (if already imported - else return None).""" if (modin := sys.modules.get("modin", None)) is not None: return modin.pandas return None def get_cudf() -> Any: """Get cudf module (if already imported - else return None).""" return sys.modules.get("cudf", None) def get_cupy() -> Any: """Get cupy module (if already imported - else return None).""" return sys.modules.get("cupy", None) def get_pyarrow() -> Any: # pragma: no cover """Get pyarrow module (if already imported - else return None).""" return sys.modules.get("pyarrow", None) def get_numpy() -> Any: """Get numpy module (if already imported - else return None).""" return sys.modules.get("numpy", None) def get_dask() -> Any: """Get dask (if already imported - else return None).""" return sys.modules.get("dask", None) def get_dask_dataframe() -> Any: """Get dask.dataframe module (if already imported - else return None).""" return sys.modules.get("dask.dataframe", None) def get_duckdb() -> Any: """Get duckdb module (if already imported - else return None).""" return sys.modules.get("duckdb", None) def get_ibis() -> Any: """Get ibis module (if already imported - else return None).""" return sys.modules.get("ibis", None) def get_dask_expr() -> Any: # pragma: no cover """Get dask_expr module (if already imported - else return None).""" return sys.modules.get("dask_expr", None) def get_pyspark() -> Any: # pragma: no cover """Get pyspark module (if already imported - else return None).""" return sys.modules.get("pyspark", None) def get_pyspark_sql() -> Any: """Get pyspark.sql module (if already imported - else return None).""" return sys.modules.get("pyspark.sql", None) def get_sqlframe() -> Any: """Get sqlframe module (if already imported - else return None).""" return sys.modules.get("sqlframe", None) def is_pandas_dataframe(df: Any) -> TypeIs[pd.DataFrame]: """Check whether `df` is a pandas DataFrame without importing pandas.""" return ((pd := get_pandas()) is not None and isinstance(df, pd.DataFrame)) or any( (mod := sys.modules.get(module_name, None)) is not None and isinstance(df, mod.pandas.DataFrame) for module_name in IMPORT_HOOKS ) def is_pandas_series(ser: Any) -> TypeIs[pd.Series[Any]]: """Check whether `ser` is a pandas Series without importing pandas.""" return ((pd := get_pandas()) is not None and isinstance(ser, pd.Series)) or any( (mod := sys.modules.get(module_name, None)) is not None and isinstance(ser, mod.pandas.Series) for module_name in IMPORT_HOOKS ) def is_pandas_index(index: Any) -> TypeIs[pd.Index[Any]]: """Check whether `index` is a pandas Index without importing pandas.""" return ((pd := get_pandas()) is not None and isinstance(index, pd.Index)) or any( (mod := sys.modules.get(module_name, None)) is not None and isinstance(index, mod.pandas.Index) for module_name in IMPORT_HOOKS ) def is_modin_dataframe(df: Any) -> TypeIs[mpd.DataFrame]: """Check whether `df` is a modin DataFrame without importing modin.""" return (mpd := get_modin()) is not None and isinstance(df, mpd.DataFrame) def is_modin_series(ser: Any) -> TypeIs[mpd.Series]: """Check whether `ser` is a modin Series without importing modin.""" return (mpd := get_modin()) is not None and isinstance(ser, mpd.Series) def is_modin_index(index: Any) -> TypeIs[mpd.Index]: """Check whether `index` is a modin Index without importing modin.""" return (mpd := get_modin()) is not None and isinstance( index, mpd.Index ) # pragma: no cover def is_cudf_dataframe(df: Any) -> TypeIs[cudf.DataFrame]: """Check whether `df` is a cudf DataFrame without importing cudf.""" return (cudf := get_cudf()) is not None and isinstance(df, cudf.DataFrame) def is_cudf_series(ser: Any) -> TypeIs[cudf.Series[Any]]: """Check whether `ser` is a cudf Series without importing cudf.""" return (cudf := get_cudf()) is not None and isinstance(ser, cudf.Series) def is_cudf_index(index: Any) -> TypeIs[cudf.Index]: """Check whether `index` is a cudf Index without importing cudf.""" return (cudf := get_cudf()) is not None and isinstance( index, cudf.Index ) # pragma: no cover def is_dask_dataframe(df: Any) -> TypeIs[dd.DataFrame]: """Check whether `df` is a Dask DataFrame without importing Dask.""" return (dd := get_dask_dataframe()) is not None and isinstance(df, dd.DataFrame) def is_duckdb_relation(df: Any) -> TypeIs[duckdb.DuckDBPyRelation]: """Check whether `df` is a DuckDB Relation without importing DuckDB.""" return (duckdb := get_duckdb()) is not None and isinstance( df, duckdb.DuckDBPyRelation ) def is_ibis_table(df: Any) -> TypeIs[ibis.Table]: """Check whether `df` is a Ibis Table without importing Ibis.""" return (ibis := get_ibis()) is not None and isinstance(df, ibis.expr.types.Table) def is_polars_dataframe(df: Any) -> TypeIs[pl.DataFrame]: """Check whether `df` is a Polars DataFrame without importing Polars.""" return (pl := get_polars()) is not None and isinstance(df, pl.DataFrame) def is_polars_lazyframe(df: Any) -> TypeIs[pl.LazyFrame]: """Check whether `df` is a Polars LazyFrame without importing Polars.""" return (pl := get_polars()) is not None and isinstance(df, pl.LazyFrame) def is_polars_series(ser: Any) -> TypeIs[pl.Series]: """Check whether `ser` is a Polars Series without importing Polars.""" return (pl := get_polars()) is not None and isinstance(ser, pl.Series) def is_pyarrow_chunked_array( ser: Any | ArrowChunkedArray, ) -> TypeIs[ArrowChunkedArray]: """Check whether `ser` is a PyArrow ChunkedArray without importing PyArrow.""" return (pa := get_pyarrow()) is not None and isinstance(ser, pa.ChunkedArray) def is_pyarrow_table(df: Any) -> TypeIs[pa.Table]: """Check whether `df` is a PyArrow Table without importing PyArrow.""" return (pa := get_pyarrow()) is not None and isinstance(df, pa.Table) def is_pyspark_dataframe(df: Any) -> TypeIs[pyspark_sql.DataFrame]: """Check whether `df` is a PySpark DataFrame without importing PySpark.""" return bool( (pyspark_sql := get_pyspark_sql()) is not None and isinstance(df, pyspark_sql.DataFrame) ) def is_sqlframe_dataframe(df: Any) -> TypeIs[SQLFrameDataFrame]: """Check whether `df` is a SQLFrame DataFrame without importing SQLFrame.""" if get_sqlframe() is not None: from sqlframe.base.dataframe import BaseDataFrame return isinstance(df, BaseDataFrame) return False # pragma: no cover def is_numpy_array(arr: Any | _NDArray[_ShapeT]) -> TypeIs[_NDArray[_ShapeT]]: """Check whether `arr` is a NumPy Array without importing NumPy.""" return (np := get_numpy()) is not None and isinstance(arr, np.ndarray) def is_numpy_array_1d(arr: Any) -> TypeIs[_1DArray]: """Check whether `arr` is a 1D NumPy Array without importing NumPy.""" return is_numpy_array(arr) and arr.ndim == 1 def is_numpy_array_2d(arr: Any) -> TypeIs[_2DArray]: """Check whether `arr` is a 2D NumPy Array without importing NumPy.""" return is_numpy_array(arr) and arr.ndim == 2 def is_numpy_scalar(scalar: Any) -> TypeGuard[np.generic]: """Check whether `scalar` is a NumPy Scalar without importing NumPy.""" # NOTE: Needs to stay as `TypeGuard` # - Used in `Series.__getitem__`, but not annotated # - `TypeGuard` is *hiding* that the check introduces an intersection return (np := get_numpy()) is not None and np.isscalar(scalar) def is_pandas_like_dataframe(df: Any) -> bool: """Check whether `df` is a pandas-like DataFrame without doing any imports. By "pandas-like", we mean: pandas, Modin, cuDF. """ return is_pandas_dataframe(df) or is_modin_dataframe(df) or is_cudf_dataframe(df) def is_pandas_like_series(ser: Any) -> bool: """Check whether `ser` is a pandas-like Series without doing any imports. By "pandas-like", we mean: pandas, Modin, cuDF. """ return is_pandas_series(ser) or is_modin_series(ser) or is_cudf_series(ser) def is_pandas_like_index(index: Any) -> bool: """Check whether `index` is a pandas-like Index without doing any imports. By "pandas-like", we mean: pandas, Modin, cuDF. """ return ( is_pandas_index(index) or is_modin_index(index) or is_cudf_index(index) ) # pragma: no cover def is_into_series(native_series: Any | IntoSeriesT) -> TypeIs[IntoSeriesT]: """Check whether `native_series` can be converted to a Narwhals Series. Arguments: native_series: The object to check. Returns: `True` if `native_series` can be converted to a Narwhals Series, `False` otherwise. Examples: >>> import pandas as pd >>> import polars as pl >>> import numpy as np >>> import narwhals as nw >>> s_pd = pd.Series([1, 2, 3]) >>> s_pl = pl.Series([1, 2, 3]) >>> np_arr = np.array([1, 2, 3]) >>> nw.dependencies.is_into_series(s_pd) True >>> nw.dependencies.is_into_series(s_pl) True >>> nw.dependencies.is_into_series(np_arr) False """ from narwhals.series import Series return ( isinstance(native_series, Series) or hasattr(native_series, "__narwhals_series__") or is_polars_series(native_series) or is_pyarrow_chunked_array(native_series) or is_pandas_like_series(native_series) ) def is_into_dataframe(native_dataframe: Any | IntoDataFrameT) -> TypeIs[IntoDataFrameT]: """Check whether `native_dataframe` can be converted to a Narwhals DataFrame. Arguments: native_dataframe: The object to check. Returns: `True` if `native_dataframe` can be converted to a Narwhals DataFrame, `False` otherwise. Examples: >>> import pandas as pd >>> import polars as pl >>> import numpy as np >>> from narwhals.dependencies import is_into_dataframe >>> df_pd = pd.DataFrame({"a": [1, 2, 3], "b": [4, 5, 6]}) >>> df_pl = pl.DataFrame({"a": [1, 2, 3], "b": [4, 5, 6]}) >>> np_arr = np.array([[1, 4], [2, 5], [3, 6]]) >>> is_into_dataframe(df_pd) True >>> is_into_dataframe(df_pl) True >>> is_into_dataframe(np_arr) False """ from narwhals.dataframe import DataFrame return ( isinstance(native_dataframe, DataFrame) or hasattr(native_dataframe, "__narwhals_dataframe__") or is_polars_dataframe(native_dataframe) or is_pyarrow_table(native_dataframe) or is_pandas_like_dataframe(native_dataframe) ) def is_narwhals_dataframe( df: Any | DataFrame[DataFrameT], ) -> TypeIs[DataFrame[DataFrameT]]: """Check whether `df` is a Narwhals DataFrame. This is useful if you expect a user to pass in a Narwhals DataFrame directly, and you want to catch both ``narwhals.DataFrame`` and ``narwhals.stable.v1.DataFrame`. """ from narwhals.dataframe import DataFrame return isinstance(df, DataFrame) def is_narwhals_lazyframe(lf: Any | LazyFrame[FrameT]) -> TypeIs[LazyFrame[FrameT]]: """Check whether `lf` is a Narwhals LazyFrame. This is useful if you expect a user to pass in a Narwhals LazyFrame directly, and you want to catch both ``narwhals.LazyFrame`` and ``narwhals.stable.v1.LazyFrame`. """ from narwhals.dataframe import LazyFrame return isinstance(lf, LazyFrame) def is_narwhals_series(ser: Any | Series[IntoSeriesT]) -> TypeIs[Series[IntoSeriesT]]: """Check whether `ser` is a Narwhals Series. This is useful if you expect a user to pass in a Narwhals Series directly, and you want to catch both ``narwhals.Series`` and ``narwhals.stable.v1.Series`. """ from narwhals.series import Series return isinstance(ser, Series) __all__ = [ "get_cudf", "get_ibis", "get_modin", "get_numpy", "get_pandas", "get_polars", "get_pyarrow", "is_cudf_dataframe", "is_cudf_series", "is_dask_dataframe", "is_ibis_table", "is_into_dataframe", "is_into_series", "is_modin_dataframe", "is_modin_series", "is_narwhals_dataframe", "is_narwhals_lazyframe", "is_narwhals_series", "is_numpy_array", "is_pandas_dataframe", "is_pandas_index", "is_pandas_like_dataframe", "is_pandas_like_series", "is_pandas_series", "is_polars_dataframe", "is_polars_lazyframe", "is_polars_series", "is_pyarrow_chunked_array", "is_pyarrow_table", ]