Merge branch 'narwhals-dev:main' into main

docs/api-reference/expressions.md

@@ -4,6 +4,7 @@
     handler: python
     options:
       members:
+        - abs
         - alias
         - all
         - any

docs/api-reference/series.md

@@ -4,6 +4,7 @@
     handler: python
     options:
       members:
+        - abs
         - alias
         - all
         - any

docs/installation.md

@@ -11,6 +11,6 @@ Then, if you start the Python REPL and see the following:
 ```python
 >>> import narwhals
 >>> narwhals.__version__
-'0.9.27'
+'0.9.28'
 ```
 then installation worked correctly!

narwhals/__init__.py

@@ -42,7 +42,7 @@
 from narwhals.utils import maybe_convert_dtypes
 from narwhals.utils import maybe_set_index
 
-__version__ = "0.9.27"
+__version__ = "0.9.28"
 
 __all__ = [
     "selectors",

narwhals/_arrow/expr.py

@@ -71,6 +71,9 @@ def __narwhals_namespace__(self) -> ArrowNamespace:
     def cast(self, dtype: DType) -> Self:
         return reuse_series_implementation(self, "cast", dtype)  # type: ignore[type-var]
 
+    def abs(self) -> Self:
+        return reuse_series_implementation(self, "abs")  # type: ignore[type-var]
+
     def cum_sum(self) -> Self:
         return reuse_series_implementation(self, "cum_sum")  # type: ignore[type-var]
 

narwhals/_arrow/series.py

@@ -78,6 +78,10 @@ def alias(self, name: str) -> Self:
     def dtype(self) -> DType:
         return translate_dtype(self._series.type)
 
+    def abs(self) -> Self:
+        pc = get_pyarrow_compute()
+        return self._from_series(pc.abs(self._series))
+
     def cum_sum(self) -> Self:
         pc = get_pyarrow_compute()
         return self._from_series(pc.cumulative_sum(self._series))

narwhals/_pandas_like/expr.py

@@ -216,6 +216,9 @@ def drop_nulls(self) -> Self:
     def sort(self, *, descending: bool = False) -> Self:
         return reuse_series_implementation(self, "sort", descending=descending)
 
+    def abs(self) -> Self:
+        return reuse_series_implementation(self, "abs")
+
     def cum_sum(self) -> Self:
         return reuse_series_implementation(self, "cum_sum")
 

narwhals/_pandas_like/series.py

@@ -401,6 +401,9 @@ def sample(
         ser = self._series
         return self._from_series(ser.sample(n=n, frac=fraction, replace=with_replacement))
 
+    def abs(self) -> PandasSeries:
+        return self._from_series(self._series.abs())
+
     def cum_sum(self) -> PandasSeries:
         return self._from_series(self._series.cumsum())
 

narwhals/dataframe.py

@@ -399,9 +399,9 @@ def __getitem__(self, item: Sequence[int]) -> Series: ...
     def __getitem__(self, item: str) -> Series: ...
 
     @overload
-    def __getitem__(self, item: slice) -> DataFrame: ...
+    def __getitem__(self, item: slice) -> Self: ...
 
-    def __getitem__(self, item: str | slice | Sequence[int]) -> Series | DataFrame:
+    def __getitem__(self, item: str | slice | Sequence[int]) -> Series | Self:
         if isinstance(item, str):
             from narwhals.series import Series
 
@@ -1649,7 +1649,7 @@ def is_unique(self: Self) -> Series:
 
         return Series(self._dataframe.is_unique())
 
-    def null_count(self: Self) -> DataFrame:
+    def null_count(self: Self) -> Self:
         r"""
         Create a new DataFrame that shows the null counts per column.
 
@@ -1814,7 +1814,7 @@ def __repr__(self) -> str:  # pragma: no cover
             + "┘"
         )
 
-    def __getitem__(self, item: str | slice) -> Series | DataFrame:
+    def __getitem__(self, item: str | slice) -> Series | Self:
         raise TypeError("Slicing is not supported on LazyFrame")
 
     def collect(self) -> DataFrame: