wip

Author: MarcoGorelli

narwhals/pandas_like/__init__.py

@@ -1,24 +0,0 @@
-from __future__ import annotations
-
-from typing import TYPE_CHECKING
-from typing import Any
-
-from narwhals.pandas_like.dataframe import LazyFrame
-from narwhals.pandas_like.namespace import Namespace  # noqa: F401
-
-if TYPE_CHECKING:
-    from narwhals.spec import LazyFrame as LazyFrameT
-    from narwhals.spec import Namespace as NamespaceT
-
-
-def translate(
-    df: Any,
-    implementation: str,
-    api_version: str,
-) -> tuple[LazyFrameT, NamespaceT]:
-    df = LazyFrame(
-        df,
-        api_version=api_version,
-        implementation=implementation,
-    )
-    return df, df.__lazyframe_namespace__()

narwhals/pandas_like/dataframe.py

@@ -6,13 +6,12 @@
 from typing import Iterable
 from typing import Literal
 
-import narwhals
 from narwhals.spec import DataFrame as DataFrameT
 from narwhals.spec import GroupBy as GroupByT
 from narwhals.spec import IntoExpr
-from narwhals.spec import LazyFrame as LazyFrameT
+from narwhals.spec import LazyFrame as LazyFrameProtocol
 from narwhals.spec import LazyGroupBy as LazyGroupByT
-from narwhals.spec import Namespace as NamespaceT
+from narwhals.spec import Namespace as NamespaceProtocol
 from narwhals.utils import evaluate_into_exprs
 from narwhals.utils import flatten_str
 from narwhals.utils import horizontal_concat
@@ -23,6 +22,8 @@
 
     from typing_extensions import Self
 
+    from narwhals.pandas_like.namespace import Namespace
+
 
 class DataFrame(DataFrameT):
     """dataframe object"""
@@ -84,8 +85,10 @@ def dataframe(self) -> Any:
 
     def __dataframe_namespace__(
         self,
-    ) -> NamespaceT:
-        return narwhals.pandas_like.namespace.Namespace(
+    ) -> Namespace:
+        from narwhals.pandas_like.namespace import Namespace
+
+        return Namespace(
             api_version=self.api_version,
             implementation=self._implementation,  # type: ignore[attr-defined]
         )
@@ -169,7 +172,7 @@ def to_pandas(self) -> Any:
         raise TypeError(msg)
 
 
-class LazyFrame(LazyFrameT):
+class LazyFrame(LazyFrameProtocol):
     """dataframe object"""
 
     def __init__(
@@ -233,8 +236,10 @@ def dataframe(self) -> Any:
 
     def __lazyframe_namespace__(
         self,
-    ) -> NamespaceT:
-        return narwhals.pandas_like.namespace.Namespace(
+    ) -> NamespaceProtocol:
+        from narwhals.pandas_like.namespace import Namespace
+
+        return Namespace(
             api_version=self.api_version,
             implementation=self._implementation,  # type: ignore[attr-defined]
         )

narwhals/pandas_like/expr.py

@@ -7,16 +7,16 @@
 from narwhals.spec import DataFrame as DataFrameT
 from narwhals.spec import Expr as ExprT
 from narwhals.spec import ExprStringNamespace as ExprStringNamespaceT
-from narwhals.spec import LazyFrame as LazyFrameT
-from narwhals.spec import Namespace as NamespaceT
+from narwhals.spec import LazyFrame as LazyFrameProtocol
+from narwhals.spec import Namespace as NamespaceProtocol
 from narwhals.spec import Series as SeriesT
 from narwhals.utils import register_expression_call
 
 
 class Expr(ExprT):
     def __init__(  # noqa: PLR0913
         self,
-        call: Callable[[DataFrameT | LazyFrameT], list[SeriesT]],
+        call: Callable[[DataFrameT | LazyFrameProtocol], list[SeriesT]],
         *,
         depth: int | None,
         function_name: str | None,
@@ -62,7 +62,7 @@ def from_column_names(
             implementation=implementation,
         )
 
-    def __expr_namespace__(self) -> NamespaceT:
+    def __expr_namespace__(self) -> NamespaceProtocol:
         from narwhals.pandas_like.namespace import Namespace
 
         return Namespace(

narwhals/pandas_like/group_by_object.py

@@ -8,7 +8,7 @@
 from narwhals.spec import DataFrame as DataFrameT
 from narwhals.spec import GroupBy as GroupByT
 from narwhals.spec import IntoExpr
-from narwhals.spec import LazyFrame as LazyFrameT
+from narwhals.spec import LazyFrame as LazyFrameProtocol
 from narwhals.spec import LazyGroupBy as LazyGroupByT
 from narwhals.utils import dataframe_from_dict
 from narwhals.utils import evaluate_simple_aggregation
@@ -37,7 +37,7 @@ def agg(
 
 
 class LazyGroupBy(LazyGroupByT):
-    def __init__(self, df: LazyFrameT, keys: list[str], api_version: str) -> None:
+    def __init__(self, df: LazyFrameProtocol, keys: list[str], api_version: str) -> None:
         self._df = df
         self._keys = list(keys)
         self.api_version = api_version
@@ -46,7 +46,7 @@ def agg(
         self,
         *aggs: IntoExpr | Iterable[IntoExpr],
         **named_aggs: IntoExpr,
-    ) -> LazyFrameT:
+    ) -> LazyFrameProtocol:
         df = self._df.dataframe  # type: ignore[attr-defined]
         exprs = parse_into_exprs(
             get_namespace(self._df),

narwhals/pandas_like/namespace.py

@@ -13,16 +13,16 @@
 from narwhals.spec import DataFrame as DataFrameT
 from narwhals.spec import Expr as ExprT
 from narwhals.spec import IntoExpr
-from narwhals.spec import LazyFrame as LazyFrameT
-from narwhals.spec import Namespace as NamespaceT
+from narwhals.spec import LazyFrame as LazyFrameProtocol
+from narwhals.spec import Namespace as NamespaceProtocol
 from narwhals.spec import Series as SeriesT
 from narwhals.utils import flatten_str
 from narwhals.utils import horizontal_concat
 from narwhals.utils import parse_into_exprs
 from narwhals.utils import series_from_iterable
 
 
-class Namespace(NamespaceT):
+class Namespace(NamespaceProtocol):
     def __init__(self, *, api_version: str, implementation: str) -> None:
         self.__dataframeapi_version__ = api_version
         self.api_version = api_version
@@ -110,7 +110,7 @@ def len(self) -> ExprT:
 
     def _create_expr_from_callable(  # noqa: PLR0913
         self,
-        func: Callable[[DataFrameT | LazyFrameT], list[SeriesT]],
+        func: Callable[[DataFrameT | LazyFrameProtocol], list[SeriesT]],
         *,
         depth: int,
         function_name: str | None,

narwhals/pandas_like/series.py

@@ -1,14 +1,17 @@
 from __future__ import annotations
 
+from typing import TYPE_CHECKING
 from typing import Any
 
 from pandas.api.types import is_extension_array_dtype
 
-import narwhals
 from narwhals.spec import Series as SeriesT
 from narwhals.utils import item
 from narwhals.utils import validate_column_comparand
 
+if TYPE_CHECKING:
+    from narwhals.pandas_like.namespace import Namespace
+
 
 class Series(SeriesT):
     def __init__(
@@ -53,8 +56,10 @@ def _from_series(self, series: Any) -> Series:
 
     def __series_namespace__(
         self,
-    ) -> narwhals.pandas_like.Namespace:
-        return narwhals.pandas_like.Namespace(
+    ) -> Namespace:
+        from narwhals.pandas_like.namespace import Namespace
+
+        return Namespace(
             api_version=self.api_version,
             implementation=self._implementation,
         )

narwhals/translate.py

@@ -27,7 +27,7 @@ def to_polars_api(df: Any, version: str) -> tuple[LazyFrame, Namespace]:
         pass
     else:
         if isinstance(df, pd.DataFrame):
-            from narwhals.pandas_like import translate
+            from narwhals.pandas_like.translate import translate
 
             return translate(df, api_version=version, implementation="pandas")
     try:
@@ -36,7 +36,7 @@ def to_polars_api(df: Any, version: str) -> tuple[LazyFrame, Namespace]:
         pass
     else:
         if isinstance(df, cudf.DataFrame):
-            from narwhals.pandas_like import translate
+            from narwhals.pandas_like.translate import translate
 
             return translate(df, api_version=version, implementation="cudf")
     try:
@@ -45,7 +45,7 @@ def to_polars_api(df: Any, version: str) -> tuple[LazyFrame, Namespace]:
         pass
     else:
         if isinstance(df, mpd.DataFrame):
-            from narwhals.pandas_like import translate
+            from narwhals.pandas_like.translate import translate
 
             return translate(df, api_version=version, implementation="modin")
     msg = f"Could not translate DataFrame {type(df)}, please open a feature request."
@@ -55,7 +55,7 @@ def to_polars_api(df: Any, version: str) -> tuple[LazyFrame, Namespace]:
 def quick_translate(df: Any, version: str, implementation: str) -> DataFrame:
     """Translate to Polars API, if implementation is already known."""
     if implementation in ("pandas", "cudf"):
-        from narwhals.pandas_like import translate
+        from narwhals.pandas_like.translate import translate
 
         df, _pl = translate(df, api_version=version, implementation=implementation)
         return df
@@ -96,3 +96,18 @@ def get_namespace(obj: Any, implementation: str | None = None) -> Namespace:
         return obj.__expr_namespace__()
     msg = f"Could not find namespace for object {obj}"
     raise TypeError(msg)
+
+
+def translate(
+    df: Any,
+    implementation: str,
+    api_version: str,
+) -> tuple[LazyFrame, Namespace]:
+    from narwhals.pandas_like.dataframe import LazyFrame
+
+    df = LazyFrame(
+        df,
+        api_version=api_version,
+        implementation=implementation,
+    )
+    return df, df.__lazyframe_namespace__()