reduce diff

narwhals/_expression_parsing.py

@@ -338,7 +338,7 @@ def extract_compliant(
 
 
 def operation_is_order_dependent(*args: IntoExpr | Any) -> bool:
-    # If any arg is an Expr, we look at `_is_order_dependent`. If it isn't,
+    # If an arg is an Expr, we look at `_is_order_dependent`. If it isn't,
     # it means that it was a scalar (e.g. nw.col('a') + 1) or a column name,
     # neither of which is order-dependent, so we default to `False`.
     return any(getattr(x, "_is_order_dependent", False) for x in args)

narwhals/dataframe.py

@@ -65,16 +65,16 @@ def _from_compliant_dataframe(self, df: Any) -> Self:
             level=self._level,
         )
 
-    @abstractmethod
-    def _extract_compliant(self, arg: Any) -> Any:
-        raise NotImplementedError
-
     def _flatten_and_extract(self, *args: Any, **kwargs: Any) -> Any:
         """Process `args` and `kwargs`, extracting underlying objects as we go."""
         args = [self._extract_compliant(v) for v in flatten(args)]  # type: ignore[assignment]
         kwargs = {k: self._extract_compliant(v) for k, v in kwargs.items()}
         return args, kwargs
 
+    @abstractmethod
+    def _extract_compliant(self, arg: Any) -> Any:
+        raise NotImplementedError
+
     @property
     def schema(self) -> Schema:
         return Schema(self._compliant_frame.schema.items())

narwhals/expr.py

@@ -36,10 +36,6 @@ def __init__(
     ) -> None:
         # callable from CompliantNamespace to CompliantExpr
         self._to_compliant_expr = to_compliant_expr
-
-        # For binary operations, need to do "or".
-        # For transforms, preserve.
-        # For aggs, preserve.
         self._is_order_dependent = is_order_dependent
 
     def _taxicab_norm(self) -> Self:
@@ -1236,8 +1232,7 @@ def arg_min(self) -> Self:
             b_arg_min: [[1]]
         """
         return self.__class__(
-            lambda plx: self._to_compliant_expr(plx).arg_min(),
-            is_order_dependent=self._is_order_dependent,
+            lambda plx: self._to_compliant_expr(plx).arg_min(), is_order_dependent=True
         )
 
     def arg_max(self) -> Self:
@@ -2524,7 +2519,8 @@ def drop_nulls(self) -> Self:
             a: [[2,4,3,5]]
         """
         return self.__class__(
-            lambda plx: self._to_compliant_expr(plx).drop_nulls(), is_order_dependent=True
+            lambda plx: self._to_compliant_expr(plx).drop_nulls(),
+            self._is_order_dependent,
         )
 
     def sample(
@@ -2598,7 +2594,7 @@ def sample(
             lambda plx: self._to_compliant_expr(plx).sample(
                 n, fraction=fraction, with_replacement=with_replacement, seed=seed
             ),
-            is_order_dependent=True,
+            self._is_order_dependent,
         )
 
     def over(self, *keys: str | Iterable[str]) -> Self:
@@ -3567,7 +3563,7 @@ def mode(self: Self) -> Self:
             a: [[1]]
         """
         return self.__class__(
-            lambda plx: self._to_compliant_expr(plx).mode(), is_order_dependent=False
+            lambda plx: self._to_compliant_expr(plx).mode(), self._is_order_dependent
         )
 
     def is_finite(self: Self) -> Self:

tests/expr_and_series/convert_time_zone_test.py

@@ -11,7 +11,6 @@
 from tests.utils import POLARS_VERSION
 from tests.utils import PYARROW_VERSION
 from tests.utils import Constructor
-from tests.utils import ConstructorEager
 from tests.utils import assert_equal_data
 from tests.utils import is_windows
 

tests/expr_and_series/replace_strict_test.py

@@ -19,9 +19,7 @@
 )
 @pytest.mark.parametrize("return_dtype", [nw.String(), None])
 def test_replace_strict(
-    constructor: Constructor,
-    request: pytest.FixtureRequest,
-    return_dtype: DType | None,
+    constructor: Constructor, request: pytest.FixtureRequest, return_dtype: DType | None
 ) -> None:
     if "dask" in str(constructor):
         request.applymarker(pytest.mark.xfail)

tests/expr_and_series/replace_time_zone_test.py

@@ -10,7 +10,6 @@
 from tests.utils import PANDAS_VERSION
 from tests.utils import PYARROW_VERSION
 from tests.utils import Constructor
-from tests.utils import ConstructorEager
 from tests.utils import assert_equal_data
 from tests.utils import is_windows
 

tests/expr_and_series/str/to_datetime_test.py

@@ -8,10 +8,10 @@
 
 import narwhals.stable.v1 as nw
 from narwhals._arrow.utils import parse_datetime_format
-from tests.utils import Constructor
 from tests.utils import assert_equal_data
 
 if TYPE_CHECKING:
+    from tests.utils import Constructor
     from tests.utils import ConstructorEager
 
 data = {"a": ["2020-01-01T12:34:56"]}

tests/frame/drop_test.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from contextlib import nullcontext as does_not_raise
+from typing import TYPE_CHECKING
 from typing import Any
 
 import pytest
@@ -9,7 +10,9 @@
 import narwhals.stable.v1 as nw
 from narwhals.exceptions import ColumnNotFoundError
 from tests.utils import POLARS_VERSION
-from tests.utils import Constructor
+
+if TYPE_CHECKING:
+    from tests.utils import Constructor
 
 
 @pytest.mark.parametrize(

tests/frame/schema_test.py

@@ -13,9 +13,9 @@
 
 import narwhals.stable.v1 as nw
 from tests.utils import PANDAS_VERSION
-from tests.utils import Constructor
 
 if TYPE_CHECKING:
+    from tests.utils import Constructor
     from tests.utils import ConstructorEager
 
 

utils/check_api_reference.py

@@ -184,7 +184,9 @@
 for namespace in NAMESPACES:
     expr_methods = [
         i
-        for i in getattr(nw.Expr(lambda: 0, is_order_dependent=True), namespace).__dir__()
+        for i in getattr(
+            nw.Expr(lambda: 0, is_order_dependent=False), namespace
+        ).__dir__()
         if not i[0].isupper() and i[0] != "_"
     ]
     with open(f"docs/api-reference/expr_{namespace}.md") as fd:
@@ -226,7 +228,7 @@
 # Check Expr vs Series
 expr = [
     i
-    for i in nw.Expr(lambda: 0, is_order_dependent=True).__dir__()
+    for i in nw.Expr(lambda: 0, is_order_dependent=False).__dir__()
     if not i[0].isupper() and i[0] != "_"
 ]
 series = [
@@ -247,7 +249,9 @@
 for namespace in NAMESPACES.difference({"name"}):
     expr_internal = [
         i
-        for i in getattr(nw.Expr(lambda: 0, is_order_dependent=True), namespace).__dir__()
+        for i in getattr(
+            nw.Expr(lambda: 0, is_order_dependent=False), namespace
+        ).__dir__()
         if not i[0].isupper() and i[0] != "_"
     ]
     series_internal = [