feat: expressify lower_bound and upper_bound in is_between

docs/how_it_works.md

@@ -266,7 +266,6 @@ In order to tell whether an aggregation is simple, Narwhals uses the private `_d
 ```python exec="1" result="python" session="pandas_impl" source="above"
 print(pn.col("a").mean())
 print((pn.col("a") + 1).mean())
-print(pn.mean("a"))
 ```
 
 For simple aggregations, Narwhals can just look at `_depth` and `function_name` and figure out

narwhals/_arrow/namespace.py

@@ -348,31 +348,6 @@ def concat(
             result_table, backend_version=self._backend_version, version=self._version
         )
 
-    def sum(self: Self, *column_names: str) -> ArrowExpr:
-        return ArrowExpr.from_column_names(
-            *column_names, backend_version=self._backend_version, version=self._version
-        ).sum()
-
-    def mean(self: Self, *column_names: str) -> ArrowExpr:
-        return ArrowExpr.from_column_names(
-            *column_names, backend_version=self._backend_version, version=self._version
-        ).mean()
-
-    def median(self: Self, *column_names: str) -> ArrowExpr:
-        return ArrowExpr.from_column_names(
-            *column_names, backend_version=self._backend_version, version=self._version
-        ).median()
-
-    def max(self: Self, *column_names: str) -> ArrowExpr:
-        return ArrowExpr.from_column_names(
-            *column_names, backend_version=self._backend_version, version=self._version
-        ).max()
-
-    def min(self: Self, *column_names: str) -> ArrowExpr:
-        return ArrowExpr.from_column_names(
-            *column_names, backend_version=self._backend_version, version=self._version
-        ).min()
-
     @property
     def selectors(self: Self) -> ArrowSelectorNamespace:
         return ArrowSelectorNamespace(

narwhals/_arrow/series.py

@@ -487,6 +487,12 @@ def is_between(
         import pyarrow.compute as pc
 
         ser = self._native_series
+        _, lower_bound = broadcast_and_extract_native(
+            self, lower_bound, self._backend_version
+        )
+        _, upper_bound = broadcast_and_extract_native(
+            self, upper_bound, self._backend_version
+        )
         if closed == "left":
             ge = pc.greater_equal(ser, lower_bound)
             lt = pc.less(ser, upper_bound)

narwhals/_dask/namespace.py

@@ -91,31 +91,6 @@ def convert_if_dtype(
             kwargs={},
         )
 
-    def min(self, *column_names: str) -> DaskExpr:
-        return DaskExpr.from_column_names(
-            *column_names, backend_version=self._backend_version, version=self._version
-        ).min()
-
-    def max(self, *column_names: str) -> DaskExpr:
-        return DaskExpr.from_column_names(
-            *column_names, backend_version=self._backend_version, version=self._version
-        ).max()
-
-    def mean(self, *column_names: str) -> DaskExpr:
-        return DaskExpr.from_column_names(
-            *column_names, backend_version=self._backend_version, version=self._version
-        ).mean()
-
-    def median(self, *column_names: str) -> DaskExpr:
-        return DaskExpr.from_column_names(
-            *column_names, backend_version=self._backend_version, version=self._version
-        ).median()
-
-    def sum(self, *column_names: str) -> DaskExpr:
-        return DaskExpr.from_column_names(
-            *column_names, backend_version=self._backend_version, version=self._version
-        ).sum()
-
     def len(self) -> DaskExpr:
         import dask.dataframe as dd
         import pandas as pd

narwhals/_pandas_like/namespace.py

@@ -169,47 +169,6 @@ def _lit_pandas_series(df: PandasLikeDataFrame) -> PandasLikeSeries:
             kwargs={},
         )
 
-    # --- reduction ---
-    def sum(self, *column_names: str) -> PandasLikeExpr:
-        return PandasLikeExpr.from_column_names(
-            *column_names,
-            implementation=self._implementation,
-            backend_version=self._backend_version,
-            version=self._version,
-        ).sum()
-
-    def mean(self, *column_names: str) -> PandasLikeExpr:
-        return PandasLikeExpr.from_column_names(
-            *column_names,
-            implementation=self._implementation,
-            backend_version=self._backend_version,
-            version=self._version,
-        ).mean()
-
-    def median(self, *column_names: str) -> PandasLikeExpr:
-        return PandasLikeExpr.from_column_names(
-            *column_names,
-            implementation=self._implementation,
-            backend_version=self._backend_version,
-            version=self._version,
-        ).median()
-
-    def max(self, *column_names: str) -> PandasLikeExpr:
-        return PandasLikeExpr.from_column_names(
-            *column_names,
-            implementation=self._implementation,
-            backend_version=self._backend_version,
-            version=self._version,
-        ).max()
-
-    def min(self, *column_names: str) -> PandasLikeExpr:
-        return PandasLikeExpr.from_column_names(
-            *column_names,
-            implementation=self._implementation,
-            backend_version=self._backend_version,
-            version=self._version,
-        ).min()
-
     def len(self) -> PandasLikeExpr:
         return PandasLikeExpr(
             lambda df: [

narwhals/_pandas_like/series.py

@@ -263,6 +263,8 @@ def is_between(
         self, lower_bound: Any, upper_bound: Any, closed: str = "both"
     ) -> PandasLikeSeries:
         ser = self._native_series
+        _, lower_bound = broadcast_align_and_extract_native(self, lower_bound)
+        _, upper_bound = broadcast_align_and_extract_native(self, upper_bound)
         if closed == "left":
             res = ser.ge(lower_bound) & ser.lt(upper_bound)
         elif closed == "right":
@@ -273,7 +275,14 @@ def is_between(
             res = ser.ge(lower_bound) & ser.le(upper_bound)
         else:  # pragma: no cover
             raise AssertionError
-        return self._from_native_series(res)
+        return self._from_native_series(
+            rename(
+                res,
+                ser.name,
+                implementation=self._implementation,
+                backend_version=self._backend_version,
+            )
+        )
 
     def is_in(self, other: Any) -> PandasLikeSeries:
         ser = self._native_series

narwhals/_polars/namespace.py

@@ -128,17 +128,6 @@ def lit(self: Self, value: Any, dtype: DType | None = None) -> PolarsExpr:
             pl.lit(value), version=self._version, backend_version=self._backend_version
         )
 
-    def mean(self: Self, *column_names: str) -> PolarsExpr:
-        import polars as pl
-
-        from narwhals._polars.expr import PolarsExpr
-
-        return PolarsExpr(
-            pl.mean([*column_names]),  # type: ignore[arg-type]
-            version=self._version,
-            backend_version=self._backend_version,
-        )
-
     def mean_horizontal(self: Self, *exprs: IntoPolarsExpr) -> PolarsExpr:
         import polars as pl
 
@@ -160,17 +149,6 @@ def mean_horizontal(self: Self, *exprs: IntoPolarsExpr) -> PolarsExpr:
             backend_version=self._backend_version,
         )
 
-    def median(self: Self, *column_names: str) -> PolarsExpr:
-        import polars as pl
-
-        from narwhals._polars.expr import PolarsExpr
-
-        return PolarsExpr(
-            pl.median([*column_names]),  # type: ignore[arg-type]
-            version=self._version,
-            backend_version=self._backend_version,
-        )
-
     def concat_str(
         self,
         exprs: Iterable[IntoPolarsExpr],

narwhals/expr.py

@@ -1666,7 +1666,7 @@ def sort(self, *, descending: bool = False, nulls_last: bool = False) -> Self:
 
     # --- transform ---
     def is_between(
-        self, lower_bound: Any, upper_bound: Any, closed: str = "both"
+        self, lower_bound: Any | Self, upper_bound: Any | Self, closed: str = "both"
     ) -> Self:
         """Check if this expression is between the given lower and upper bounds.
 
@@ -1724,7 +1724,9 @@ def is_between(
         """
         return self.__class__(
             lambda plx: self._to_compliant_expr(plx).is_between(
-                lower_bound, upper_bound, closed
+                extract_compliant(plx, lower_bound),
+                extract_compliant(plx, upper_bound),
+                closed,
             )
         )
 
@@ -6034,7 +6036,7 @@ def col(*names: str | Iterable[str]) -> Expr:
     """Creates an expression that references one or more columns by their name(s).
 
     Arguments:
-        names: Name(s) of the columns to use in the aggregation function.
+        names: Name(s) of the columns to use.
 
     Returns:
         A new expression.
@@ -6293,7 +6295,7 @@ def sum(*columns: str) -> Expr:
         ----
         a: [[3]]
     """
-    return Expr(lambda plx: plx.sum(*columns))
+    return Expr(lambda plx: plx.col(*columns).sum())
 
 
 def mean(*columns: str) -> Expr:
@@ -6344,7 +6346,7 @@ def mean(*columns: str) -> Expr:
         ----
         a: [[4]]
     """
-    return Expr(lambda plx: plx.mean(*columns))
+    return Expr(lambda plx: plx.col(*columns).mean())
 
 
 def median(*columns: str) -> Expr:
@@ -6396,7 +6398,7 @@ def median(*columns: str) -> Expr:
         ----
         a: [[4]]
     """
-    return Expr(lambda plx: plx.median(*columns))
+    return Expr(lambda plx: plx.col(*columns).median())
 
 
 def min(*columns: str) -> Expr:
@@ -6447,7 +6449,7 @@ def min(*columns: str) -> Expr:
         ----
         b: [[5]]
     """
-    return Expr(lambda plx: plx.min(*columns))
+    return Expr(lambda plx: plx.col(*columns).min())
 
 
 def max(*columns: str) -> Expr:
@@ -6498,7 +6500,7 @@ def max(*columns: str) -> Expr:
         ----
         a: [[2]]
     """
-    return Expr(lambda plx: plx.max(*columns))
+    return Expr(lambda plx: plx.col(*columns).max())
 
 
 def sum_horizontal(*exprs: IntoExpr | Iterable[IntoExpr]) -> Expr:

narwhals/stable/v1/__init__.py

@@ -2319,7 +2319,7 @@ def col(*names: str | Iterable[str]) -> Expr:
     """Creates an expression that references one or more columns by their name(s).
 
     Arguments:
-        names: Name(s) of the columns to use in the aggregation function.
+        names: Name(s) of the columns to use.
 
     Returns:
         A new expression.

tests/expr_and_series/is_between_test.py

@@ -7,10 +7,6 @@
 from tests.utils import ConstructorEager
 from tests.utils import assert_equal_data
 
-data = {
-    "a": [1, 4, 2, 5],
-}
-
 
 @pytest.mark.parametrize(
     ("closed", "expected"),
@@ -22,12 +18,21 @@
     ],
 )
 def test_is_between(constructor: Constructor, closed: str, expected: list[bool]) -> None:
+    data = {"a": [1, 4, 2, 5]}
     df = nw.from_native(constructor(data))
     result = df.select(nw.col("a").is_between(1, 5, closed=closed))
     expected_dict = {"a": expected}
     assert_equal_data(result, expected_dict)
 
 
+def test_is_between_expressified(constructor: Constructor) -> None:
+    data = {"a": [1, 4, 2, 5], "b": [0, 5, 2, 4], "c": [9, 9, 9, 9]}
+    df = nw.from_native(constructor(data))
+    result = df.select(nw.col("a").is_between(nw.col("b"), nw.col("c")))
+    expected_dict = {"a": [True, False, True, True]}
+    assert_equal_data(result, expected_dict)
+
+
 @pytest.mark.parametrize(
     ("closed", "expected"),
     [
@@ -40,6 +45,7 @@ def test_is_between(constructor: Constructor, closed: str, expected: list[bool])
 def test_is_between_series(
     constructor_eager: ConstructorEager, closed: str, expected: list[bool]
 ) -> None:
+    data = {"a": [1, 4, 2, 5]}
     df = nw.from_native(constructor_eager(data), eager_only=True)
     result = df.with_columns(a=df["a"].is_between(1, 5, closed=closed))
     expected_dict = {"a": expected}