Allow str in static typing of reindex, ffill etc.

doc/whats-new.rst

@@ -43,7 +43,8 @@ Bug fixes
   By `Justus Magin <https://github.com/keewis>`_.
 - Promote floating-point numeric datetimes before decoding (:issue:`9179`, :pull:`9182`).
   By `Justus Magin <https://github.com/keewis>`_.
-
+- Fiy static typing of tolerance arguments by allowing `str` type (:issue:`8892`, :pull:`9194`).
+  By `Michael Niklas <https://github.com/headtr1ck>`_.
 
 Documentation
 ~~~~~~~~~~~~~

xarray/core/alignment.py

@@ -137,7 +137,7 @@ def __init__(
         exclude_dims: str | Iterable[Hashable] = frozenset(),
         exclude_vars: Iterable[Hashable] = frozenset(),
         method: str | None = None,
-        tolerance: int | float | Iterable[int | float] | None = None,
+        tolerance: float | Iterable[float] | str | None = None,
         copy: bool = True,
         fill_value: Any = dtypes.NA,
         sparse: bool = False,
@@ -965,7 +965,7 @@ def reindex(
     obj: T_Alignable,
     indexers: Mapping[Any, Any],
     method: str | None = None,
-    tolerance: int | float | Iterable[int | float] | None = None,
+    tolerance: float | Iterable[float] | str | None = None,
     copy: bool = True,
     fill_value: Any = dtypes.NA,
     sparse: bool = False,
@@ -1004,7 +1004,7 @@ def reindex_like(
     obj: T_Alignable,
     other: Dataset | DataArray,
     method: str | None = None,
-    tolerance: int | float | Iterable[int | float] | None = None,
+    tolerance: float | Iterable[float] | str | None = None,
     copy: bool = True,
     fill_value: Any = dtypes.NA,
 ) -> T_Alignable:

xarray/core/dataarray.py

@@ -1909,7 +1909,7 @@ def reindex_like(
         other: T_DataArrayOrSet,
         *,
         method: ReindexMethodOptions = None,
-        tolerance: int | float | Iterable[int | float] | None = None,
+        tolerance: float | Iterable[float] | str | None = None,
         copy: bool = True,
         fill_value=dtypes.NA,
     ) -> Self:
@@ -1936,7 +1936,7 @@ def reindex_like(
             - backfill / bfill: propagate next valid index value backward
             - nearest: use nearest valid index value
 
-        tolerance : optional
+        tolerance : float | Iterable[float] | str | None, default: None
             Maximum distance between original and new labels for inexact
             matches. The values of the index at the matching locations must
             satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
@@ -2096,7 +2096,7 @@ def reindex(
         indexers: Mapping[Any, Any] | None = None,
         *,
         method: ReindexMethodOptions = None,
-        tolerance: float | Iterable[float] | None = None,
+        tolerance: float | Iterable[float] | str | None = None,
         copy: bool = True,
         fill_value=dtypes.NA,
         **indexers_kwargs: Any,
@@ -2126,7 +2126,7 @@ def reindex(
             - backfill / bfill: propagate next valid index value backward
             - nearest: use nearest valid index value
 
-        tolerance : float | Iterable[float] | None, default: None
+        tolerance : float | Iterable[float] | str | None, default: None
             Maximum distance between original and new labels for inexact
             matches. The values of the index at the matching locations must
             satisfy the equation ``abs(index[indexer] - target) <= tolerance``.

xarray/core/dataset.py

@@ -3499,7 +3499,7 @@ def reindex_like(
         self,
         other: T_Xarray,
         method: ReindexMethodOptions = None,
-        tolerance: int | float | Iterable[int | float] | None = None,
+        tolerance: float | Iterable[float] | str | None = None,
         copy: bool = True,
         fill_value: Any = xrdtypes.NA,
     ) -> Self:
@@ -3526,7 +3526,7 @@ def reindex_like(
             - "backfill" / "bfill": propagate next valid index value backward
             - "nearest": use nearest valid index value
 
-        tolerance : optional
+        tolerance : float | Iterable[float] | str | None, default: None
             Maximum distance between original and new labels for inexact
             matches. The values of the index at the matching locations must
             satisfy the equation ``abs(index[indexer] - target) <= tolerance``.
@@ -3569,7 +3569,7 @@ def reindex(
         self,
         indexers: Mapping[Any, Any] | None = None,
         method: ReindexMethodOptions = None,
-        tolerance: int | float | Iterable[int | float] | None = None,
+        tolerance: float | Iterable[float] | str | None = None,
         copy: bool = True,
         fill_value: Any = xrdtypes.NA,
         **indexers_kwargs: Any,
@@ -3594,7 +3594,7 @@ def reindex(
             - "backfill" / "bfill": propagate next valid index value backward
             - "nearest": use nearest valid index value
 
-        tolerance : optional
+        tolerance : float | Iterable[float] | str | None, default: None
             Maximum distance between original and new labels for inexact
             matches. The values of the index at the matching locations must
             satisfy the equation ``abs(index[indexer] - target) <= tolerance``.

xarray/core/resample.py

@@ -66,12 +66,12 @@ def _drop_coords(self) -> T_Xarray:
                 obj = obj.drop_vars([k])
         return obj
 
-    def pad(self, tolerance: float | Iterable[float] | None = None) -> T_Xarray:
+    def pad(self, tolerance: float | Iterable[float] | str | None = None) -> T_Xarray:
         """Forward fill new values at up-sampled frequency.
 
         Parameters
         ----------
-        tolerance : float | Iterable[float] | None, default: None
+        tolerance : float | Iterable[float] | str | None, default: None
             Maximum distance between original and new labels to limit
             the up-sampling method.
             Up-sampled data with indices that satisfy the equation
@@ -91,12 +91,14 @@ def pad(self, tolerance: float | Iterable[float] | None = None) -> T_Xarray:
 
     ffill = pad
 
-    def backfill(self, tolerance: float | Iterable[float] | None = None) -> T_Xarray:
+    def backfill(
+        self, tolerance: float | Iterable[float] | str | None = None
+    ) -> T_Xarray:
         """Backward fill new values at up-sampled frequency.
 
         Parameters
         ----------
-        tolerance : float | Iterable[float] | None, default: None
+        tolerance : float | Iterable[float] | str | None, default: None
             Maximum distance between original and new labels to limit
             the up-sampling method.
             Up-sampled data with indices that satisfy the equation
@@ -116,13 +118,15 @@ def backfill(self, tolerance: float | Iterable[float] | None = None) -> T_Xarray
 
     bfill = backfill
 
-    def nearest(self, tolerance: float | Iterable[float] | None = None) -> T_Xarray:
+    def nearest(
+        self, tolerance: float | Iterable[float] | str | None = None
+    ) -> T_Xarray:
         """Take new values from nearest original coordinate to up-sampled
         frequency coordinates.
 
         Parameters
         ----------
-        tolerance : float | Iterable[float] | None, default: None
+        tolerance : float | Iterable[float] | str | None, default: None
             Maximum distance between original and new labels to limit
             the up-sampling method.
             Up-sampled data with indices that satisfy the equation

xarray/tests/test_groupby.py

@@ -2037,17 +2037,17 @@ def test_upsample_tolerance(self) -> None:
         array = DataArray(np.arange(2), [("time", times)])
 
         # Forward fill
-        actual = array.resample(time="6h").ffill(tolerance="12h")  # type: ignore[arg-type] # TODO: tolerance also allows strings, same issue in .reindex.
+        actual = array.resample(time="6h").ffill(tolerance="12h")
         expected = DataArray([0.0, 0.0, 0.0, np.nan, 1.0], [("time", times_upsampled)])
         assert_identical(expected, actual)
 
         # Backward fill
-        actual = array.resample(time="6h").bfill(tolerance="12h")  # type: ignore[arg-type] # TODO: tolerance also allows strings, same issue in .reindex.
+        actual = array.resample(time="6h").bfill(tolerance="12h")
         expected = DataArray([0.0, np.nan, 1.0, 1.0, 1.0], [("time", times_upsampled)])
         assert_identical(expected, actual)
 
         # Nearest
-        actual = array.resample(time="6h").nearest(tolerance="6h")  # type: ignore[arg-type] # TODO: tolerance also allows strings, same issue in .reindex.
+        actual = array.resample(time="6h").nearest(tolerance="6h")
         expected = DataArray([0, 0, np.nan, 1, 1], [("time", times_upsampled)])
         assert_identical(expected, actual)