chore(python): Rename args f/func to function (pola-rs#7032)

py-polars/polars/datatypes.py

@@ -478,10 +478,10 @@ class Unknown(DataType):
 T = TypeVar("T")
 
 
-def cache(func: Callable[..., T]) -> T:
+def cache(function: Callable[..., T]) -> T:
     # need this to satisfy mypy issue with "@property/@cache combination"
     # See: https://github.com/python/mypy/issues/5858
-    return functools.lru_cache()(func)  # type: ignore[return-value]
+    return functools.lru_cache()(function)  # type: ignore[return-value]
 
 
 class _DataTypeMappings:

py-polars/polars/internals/dataframe/frame.py

@@ -4481,10 +4481,11 @@ def join(
             ._df
         )
 
-    @deprecate_nonkeyword_arguments(allowed_args=["self", "f", "return_dtype"])
+    @deprecated_alias(f="function")
+    @deprecate_nonkeyword_arguments(allowed_args=["self", "function", "return_dtype"])
     def apply(
         self,
-        f: Callable[[tuple[Any, ...]], Any],
+        function: Callable[[tuple[Any, ...]], Any],
         return_dtype: PolarsDataType | None = None,
         inference_size: int = 256,
     ) -> Self:
@@ -4507,7 +4508,7 @@ def apply(
 
         Parameters
         ----------
-        f
+        function
             Custom function/ lambda function.
         return_dtype
             Output type of the operation. If none given, Polars tries to infer the type.
@@ -4563,7 +4564,7 @@ def apply(
         >>> df.select(pl.col("foo") * 2 + pl.col("bar"))  # doctest: +IGNORE_RESULT
 
         """
-        out, is_df = self._df.apply(f, return_dtype, inference_size)
+        out, is_df = self._df.apply(function, return_dtype, inference_size)
         if is_df:
             return self._from_pydf(out)
         else:

py-polars/polars/internals/dataframe/groupby.py

@@ -11,7 +11,7 @@
 )
 
 import polars.internals as pli
-from polars.utils import _timedelta_to_pl_duration, redirect
+from polars.utils import _timedelta_to_pl_duration, deprecated_alias, redirect
 
 if TYPE_CHECKING:
     from polars.internals.type_aliases import (
@@ -233,7 +233,8 @@ def agg(
         )
         return self.df.__class__._from_pydf(df._df)
 
-    def apply(self, f: Callable[[pli.DataFrame], pli.DataFrame]) -> DF:
+    @deprecated_alias(f="function")
+    def apply(self, function: Callable[[pli.DataFrame], pli.DataFrame]) -> DF:
         """
         Apply a custom/user-defined function (UDF) over the groups as a sub-DataFrame.
 
@@ -251,7 +252,7 @@ def apply(self, f: Callable[[pli.DataFrame], pli.DataFrame]) -> DF:
 
         Parameters
         ----------
-        f
+        function
             Custom function.
 
         Returns
@@ -320,7 +321,7 @@ def apply(self, f: Callable[[pli.DataFrame], pli.DataFrame]) -> DF:
             raise TypeError("Cannot call `apply` when grouping by an expression.")
 
         return self.df.__class__._from_pydf(
-            self.df._df.groupby_apply(by, f, self.maintain_order)
+            self.df._df.groupby_apply(by, function, self.maintain_order)
         )
 
     def head(self, n: int = 5) -> DF:

py-polars/polars/internals/expr/expr.py

@@ -30,6 +30,7 @@
 from polars.utils import (
     _timedelta_to_pl_duration,
     deprecate_nonkeyword_arguments,
+    deprecated_alias,
     sphinx_accessor,
 )
 
@@ -774,13 +775,14 @@ def suffix(self, suffix: str) -> Self:
         """  # noqa: W505
         return self._from_pyexpr(self._pyexpr.suffix(suffix))
 
-    def map_alias(self, f: Callable[[str], str]) -> Self:
+    @deprecated_alias(f="function")
+    def map_alias(self, function: Callable[[str], str]) -> Self:
         """
         Rename the output of an expression by mapping a function over the root name.
 
         Parameters
         ----------
-        f
+        function
             Function that maps root name to new name.
 
         Examples
@@ -805,7 +807,7 @@ def map_alias(self, f: Callable[[str], str]) -> Self:
         └───────────┴───────────┘
 
         """
-        return self._from_pyexpr(self._pyexpr.map_alias(f))
+        return self._from_pyexpr(self._pyexpr.map_alias(function))
 
     def is_not(self) -> Self:
         """
@@ -3092,10 +3094,11 @@ def where(self, predicate: Expr) -> Self:
         """
         return self.filter(predicate)
 
-    @deprecate_nonkeyword_arguments(allowed_args=["self", "f", "return_dtype"])
+    @deprecated_alias(f="function")
+    @deprecate_nonkeyword_arguments(allowed_args=["self", "function", "return_dtype"])
     def map(
         self,
-        f: Callable[[pli.Series], pli.Series | Any],
+        function: Callable[[pli.Series], pli.Series | Any],
         return_dtype: PolarsDataType | None = None,
         agg_list: bool = False,
     ) -> Self:
@@ -3112,7 +3115,7 @@ def map(
 
         Parameters
         ----------
-        f
+        function
             Lambda/ function to apply.
         return_dtype
             Dtype of the output Series.
@@ -3140,12 +3143,13 @@ def map(
         """
         if return_dtype is not None:
             return_dtype = py_type_to_dtype(return_dtype)
-        return self._from_pyexpr(self._pyexpr.map(f, return_dtype, agg_list))
+        return self._from_pyexpr(self._pyexpr.map(function, return_dtype, agg_list))
 
-    @deprecate_nonkeyword_arguments(allowed_args=["self", "f", "return_dtype"])
+    @deprecated_alias(f="function")
+    @deprecate_nonkeyword_arguments(allowed_args=["self", "function", "return_dtype"])
     def apply(
         self,
-        f: Callable[[pli.Series], pli.Series] | Callable[[Any], Any],
+        function: Callable[[pli.Series], pli.Series] | Callable[[Any], Any],
         return_dtype: PolarsDataType | None = None,
         skip_nulls: bool = True,
         pass_name: bool = False,
@@ -3176,7 +3180,7 @@ def apply(
 
         Parameters
         ----------
-        f
+        function
             Lambda/ function to apply.
         return_dtype
             Dtype of the output Series.
@@ -3250,7 +3254,7 @@ def apply(
             def wrap_f(x: pli.Series) -> pli.Series:  # pragma: no cover
                 def inner(s: pli.Series) -> pli.Series:  # pragma: no cover
                     s.rename(x.name, in_place=True)
-                    return f(s)
+                    return function(s)
 
                 return x.apply(inner, return_dtype=return_dtype, skip_nulls=skip_nulls)
 
@@ -3259,7 +3263,9 @@ def inner(s: pli.Series) -> pli.Series:  # pragma: no cover
         else:
 
             def wrap_f(x: pli.Series) -> pli.Series:  # pragma: no cover
-                return x.apply(f, return_dtype=return_dtype, skip_nulls=skip_nulls)
+                return x.apply(
+                    function, return_dtype=return_dtype, skip_nulls=skip_nulls
+                )
 
             return self.map(wrap_f, agg_list=True, return_dtype=return_dtype)
 

py-polars/polars/internals/lazy_functions.py

@@ -28,6 +28,7 @@
     _time_to_pl_time,
     _timedelta_to_pl_timedelta,
     deprecate_nonkeyword_arguments,
+    deprecated_alias,
 )
 
 try:
@@ -1497,9 +1498,10 @@ def cov(
     return pli.wrap_expr(pycov(a._pyexpr, b._pyexpr))
 
 
+@deprecated_alias(f="function")
 def map(
     exprs: Sequence[str] | Sequence[pli.Expr],
-    f: Callable[[Sequence[pli.Series]], pli.Series],
+    function: Callable[[Sequence[pli.Series]], pli.Series],
     return_dtype: PolarsDataType | None = None,
 ) -> pli.Expr:
     """
@@ -1511,7 +1513,7 @@ def map(
     ----------
     exprs
         Input Series to f
-    f
+    function
         Function to apply over the input
     return_dtype
         dtype of the output Series
@@ -1523,14 +1525,17 @@ def map(
     """
     exprs = pli.selection_to_pyexpr_list(exprs)
     return pli.wrap_expr(
-        _map_mul(exprs, f, return_dtype, apply_groups=False, returns_scalar=False)
+        _map_mul(
+            exprs, function, return_dtype, apply_groups=False, returns_scalar=False
+        )
     )
 
 
-@deprecate_nonkeyword_arguments(allowed_args=["exprs", "f", "return_dtype"])
+@deprecated_alias(f="function")
+@deprecate_nonkeyword_arguments(allowed_args=["exprs", "function", "return_dtype"])
 def apply(
     exprs: Sequence[str | pli.Expr],
-    f: Callable[[Sequence[pli.Series]], pli.Series | Any],
+    function: Callable[[Sequence[pli.Series]], pli.Series | Any],
     return_dtype: PolarsDataType | None = None,
     returns_scalar: bool = True,
 ) -> pli.Expr:
@@ -1549,7 +1554,7 @@ def apply(
     ----------
     exprs
         Input Series to f
-    f
+    function
         Function to apply over the input
     return_dtype
         dtype of the output Series
@@ -1564,14 +1569,19 @@ def apply(
     exprs = pli.selection_to_pyexpr_list(exprs)
     return pli.wrap_expr(
         _map_mul(
-            exprs, f, return_dtype, apply_groups=True, returns_scalar=returns_scalar
+            exprs,
+            function,
+            return_dtype,
+            apply_groups=True,
+            returns_scalar=returns_scalar,
         )
     )
 
 
+@deprecated_alias(f="function")
 def fold(
     acc: IntoExpr,
-    f: Callable[[pli.Series, pli.Series], pli.Series],
+    function: Callable[[pli.Series, pli.Series], pli.Series],
     exprs: Sequence[pli.Expr | str] | pli.Expr,
 ) -> pli.Expr:
     """
@@ -1582,7 +1592,7 @@ def fold(
     acc
         Accumulator Expression. This is the value that will be initialized when the fold
         starts. For a sum this could for instance be lit(0).
-    f
+    function
         Function to apply over the accumulator and the value.
         Fn(acc, value) -> new_value
     exprs
@@ -1600,19 +1610,20 @@ def fold(
         exprs = [exprs]
 
     exprs = pli.selection_to_pyexpr_list(exprs)
-    return pli.wrap_expr(pyfold(acc._pyexpr, f, exprs))
+    return pli.wrap_expr(pyfold(acc._pyexpr, function, exprs))
 
 
+@deprecated_alias(f="function")
 def reduce(
-    f: Callable[[pli.Series, pli.Series], pli.Series],
+    function: Callable[[pli.Series, pli.Series], pli.Series],
     exprs: Sequence[pli.Expr | str] | pli.Expr,
 ) -> pli.Expr:
     """
     Accumulate over multiple columns horizontally/ row wise with a left fold.
 
     Parameters
     ----------
-    f
+    function
         Function to apply over the accumulator and the value.
         Fn(acc, value) -> new_value
     exprs
@@ -1628,13 +1639,14 @@ def reduce(
         exprs = [exprs]
 
     exprs = pli.selection_to_pyexpr_list(exprs)
-    return pli.wrap_expr(pyreduce(f, exprs))
+    return pli.wrap_expr(pyreduce(function, exprs))
 
 
+@deprecated_alias(f="function")
 @deprecate_nonkeyword_arguments()
 def cumfold(
     acc: IntoExpr,
-    f: Callable[[pli.Series, pli.Series], pli.Series],
+    function: Callable[[pli.Series, pli.Series], pli.Series],
     exprs: Sequence[pli.Expr | str] | pli.Expr,
     include_init: bool = False,
 ) -> pli.Expr:
@@ -1648,7 +1660,7 @@ def cumfold(
     acc
         Accumulator Expression. This is the value that will be initialized when the fold
         starts. For a sum this could for instance be lit(0).
-    f
+    function
         Function to apply over the accumulator and the value.
         Fn(acc, value) -> new_value
     exprs
@@ -1668,11 +1680,12 @@ def cumfold(
         exprs = [exprs]
 
     exprs = pli.selection_to_pyexpr_list(exprs)
-    return pli.wrap_expr(pycumfold(acc._pyexpr, f, exprs, include_init))
+    return pli.wrap_expr(pycumfold(acc._pyexpr, function, exprs, include_init))
 
 
+@deprecated_alias(f="function")
 def cumreduce(
-    f: Callable[[pli.Series, pli.Series], pli.Series],
+    function: Callable[[pli.Series, pli.Series], pli.Series],
     exprs: Sequence[pli.Expr | str] | pli.Expr,
 ) -> pli.Expr:
     """
@@ -1682,7 +1695,7 @@ def cumreduce(
 
     Parameters
     ----------
-    f
+    function
         Function to apply over the accumulator and the value.
         Fn(acc, value) -> new_value
     exprs
@@ -1694,7 +1707,7 @@ def cumreduce(
         exprs = [exprs]
 
     exprs = pli.selection_to_pyexpr_list(exprs)
-    return pli.wrap_expr(pycumreduce(f, exprs))
+    return pli.wrap_expr(pycumreduce(function, exprs))
 
 
 def any(name: str | Sequence[str] | Sequence[pli.Expr] | pli.Expr) -> pli.Expr:

py-polars/polars/internals/lazyframe/frame.py

@@ -54,6 +54,7 @@
     _process_null_values,
     _timedelta_to_pl_duration,
     deprecate_nonkeyword_arguments,
+    deprecated_alias,
     normalise_filepath,
     redirect,
 )
@@ -3867,10 +3868,11 @@ def melt(
             self._ldf.melt(id_vars, value_vars, value_name, variable_name)
         )
 
+    @deprecated_alias(f="function")
     @deprecate_nonkeyword_arguments()
     def map(
         self,
-        f: Callable[[pli.DataFrame], pli.DataFrame],
+        function: Callable[[pli.DataFrame], pli.DataFrame],
         predicate_pushdown: bool = True,
         projection_pushdown: bool = True,
         slice_pushdown: bool = True,
@@ -3886,7 +3888,7 @@ def map(
 
         Parameters
         ----------
-        f
+        function
             Lambda/ function to apply.
         predicate_pushdown
             Allow predicate pushdown optimization to pass this node.
@@ -3940,7 +3942,7 @@ def map(
 
         return self._from_pyldf(
             self._ldf.map(
-                f,
+                function,
                 predicate_pushdown,
                 projection_pushdown,
                 slice_pushdown,