Coarsen keep attrs 3376

xarray/core/common.py

@@ -742,6 +742,7 @@ def rolling(
         dim: Mapping[Hashable, int] = None,
         min_periods: int = None,
         center: bool = False,
+        keep_attrs: bool = None,
         **window_kwargs: int,
     ):
         """
@@ -758,6 +759,10 @@ def rolling(
             setting min_periods equal to the size of the window.
         center : boolean, default False
             Set the labels at the center of the window.
+        keep_attrs : bool, optional
+            If True, the object's attributes (`attrs`) will be copied from
+            the original object to the new one.  If False (default), the new
+            object will be returned without attributes.
         **window_kwargs : optional
             The keyword arguments form of ``dim``.
             One of dim or window_kwargs must be provided.
@@ -799,8 +804,11 @@ def rolling(
         core.rolling.DataArrayRolling
         core.rolling.DatasetRolling
         """
+        if keep_attrs is None:
+            keep_attrs = _get_keep_attrs(default=False)
+
         dim = either_dict_or_kwargs(dim, window_kwargs, "rolling")
-        return self._rolling_cls(self, dim, min_periods=min_periods, center=center)
+        return self._rolling_cls(self, dim, min_periods=min_periods, center=center, keep_attrs=keep_attrs)
 
     def rolling_exp(
         self,
@@ -848,6 +856,7 @@ def coarsen(
         boundary: str = "exact",
         side: Union[str, Mapping[Hashable, str]] = "left",
         coord_func: str = "mean",
+        keep_attrs: bool = None,
         **window_kwargs: int,
     ):
         """
@@ -868,8 +877,12 @@ def coarsen(
             multiple of the window size. If 'trim', the excess entries are
             dropped. If 'pad', NA will be padded.
         side : 'left' or 'right' or mapping from dimension to 'left' or 'right'
-        coord_func : function (name) that is applied to the coordintes,
+        coord_func : function (name) that is applied to the coordinates,
             or a mapping from coordinate name to function (name).
+        keep_attrs : bool, optional
+            If True, the object's attributes (`attrs`) will be copied from
+            the original object to the new one.  If False (default), the new
+            object will be returned without attributes.
 
         Returns
         -------
@@ -904,9 +917,12 @@ def coarsen(
         core.rolling.DataArrayCoarsen
         core.rolling.DatasetCoarsen
         """
+        if keep_attrs is None:
+            keep_attrs = _get_keep_attrs(default=False)
+
         dim = either_dict_or_kwargs(dim, window_kwargs, "coarsen")
         return self._coarsen_cls(
-            self, dim, boundary=boundary, side=side, coord_func=coord_func
+            self, dim, boundary=boundary, side=side, coord_func=coord_func, keep_attrs=keep_attrs
         )
 
     def resample(

xarray/core/rolling.py

@@ -7,6 +7,7 @@
 from . import dtypes, duck_array_ops, utils
 from .dask_array_ops import dask_rolling_wrapper
 from .ops import inject_reduce_methods
+from .options import _get_keep_attrs
 from .pycompat import dask_array_type
 
 try:
@@ -42,10 +43,10 @@ class Rolling:
     DataArray.rolling
     """
 
-    __slots__ = ("obj", "window", "min_periods", "center", "dim")
-    _attributes = ("window", "min_periods", "center", "dim")
+    __slots__ = ("obj", "window", "min_periods", "center", "dim", "keep_attrs")
+    _attributes = ("window", "min_periods", "center", "dim", "keep_attrs")
 
-    def __init__(self, obj, windows, min_periods=None, center=False):
+    def __init__(self, obj, windows, min_periods=None, center=False, keep_attrs=None):
         """
         Moving window object.
 
@@ -65,6 +66,10 @@ def __init__(self, obj, windows, min_periods=None, center=False):
             setting min_periods equal to the size of the window.
         center : boolean, default False
             Set the labels at the center of the window.
+        keep_attrs : bool, optional
+            If True, the object's attributes (`attrs`) will be copied from
+            the original object to the new one.  If False (default), the new
+            object will be returned without attributes.
 
         Returns
         -------
@@ -89,6 +94,10 @@ def __init__(self, obj, windows, min_periods=None, center=False):
         self.center = center
         self.dim = dim
 
+        if keep_attrs is None:
+            keep_attrs = _get_keep_attrs(default=False)
+        self.keep_attrs = keep_attrs
+
     @property
     def _min_periods(self):
         return self.min_periods if self.min_periods is not None else self.window
@@ -143,7 +152,7 @@ def count(self):
 class DataArrayRolling(Rolling):
     __slots__ = ("window_labels",)
 
-    def __init__(self, obj, windows, min_periods=None, center=False):
+    def __init__(self, obj, windows, min_periods=None, center=False, keep_attrs=None):
         """
         Moving window object for DataArray.
         You should use DataArray.rolling() method to construct this object
@@ -165,6 +174,10 @@ def __init__(self, obj, windows, min_periods=None, center=False):
             setting min_periods equal to the size of the window.
         center : boolean, default False
             Set the labels at the center of the window.
+        keep_attrs : bool, optional
+            If True, the object's attributes (`attrs`) will be copied from
+            the original object to the new one.  If False (default), the new
+            object will be returned without attributes.
 
         Returns
         -------
@@ -177,7 +190,9 @@ def __init__(self, obj, windows, min_periods=None, center=False):
         Dataset.rolling
         Dataset.groupby
         """
-        super().__init__(obj, windows, min_periods=min_periods, center=center)
+        if keep_attrs is None:
+            keep_attrs = _get_keep_attrs(default=False)
+        super().__init__(obj, windows, min_periods=min_periods, center=center, keep_attrs=keep_attrs)
 
         self.window_labels = self.obj[self.dim]
 
@@ -374,7 +389,7 @@ def _numpy_or_bottleneck_reduce(
 class DatasetRolling(Rolling):
     __slots__ = ("rollings",)
 
-    def __init__(self, obj, windows, min_periods=None, center=False):
+    def __init__(self, obj, windows, min_periods=None, center=False, keep_attrs=None):
         """
         Moving window object for Dataset.
         You should use Dataset.rolling() method to construct this object
@@ -396,6 +411,10 @@ def __init__(self, obj, windows, min_periods=None, center=False):
             setting min_periods equal to the size of the window.
         center : boolean, default False
             Set the labels at the center of the window.
+        keep_attrs : bool, optional
+            If True, the object's attributes (`attrs`) will be copied from
+            the original object to the new one.  If False (default), the new
+            object will be returned without attributes.
 
         Returns
         -------
@@ -408,15 +427,15 @@ def __init__(self, obj, windows, min_periods=None, center=False):
         Dataset.groupby
         DataArray.groupby
         """
-        super().__init__(obj, windows, min_periods, center)
+        super().__init__(obj, windows, min_periods, center, keep_attrs)
         if self.dim not in self.obj.dims:
             raise KeyError(self.dim)
         # Keep each Rolling object as a dictionary
         self.rollings = {}
         for key, da in self.obj.data_vars.items():
             # keeps rollings only for the dataset depending on slf.dim
             if self.dim in da.dims:
-                self.rollings[key] = DataArrayRolling(da, windows, min_periods, center)
+                self.rollings[key] = DataArrayRolling(da, windows, min_periods, center, keep_attrs)
 
     def _dataset_implementation(self, func, **kwargs):
         from .dataset import Dataset
@@ -466,7 +485,7 @@ def _numpy_or_bottleneck_reduce(
             **kwargs,
         )
 
-    def construct(self, window_dim, stride=1, fill_value=dtypes.NA):
+    def construct(self, window_dim, stride=1, fill_value=dtypes.NA, keep_attrs=None):
         """
         Convert this rolling object to xr.Dataset,
         where the window dimension is stacked as a new dimension
@@ -487,6 +506,9 @@ def construct(self, window_dim, stride=1, fill_value=dtypes.NA):
 
         from .dataset import Dataset
 
+        if keep_attrs is None:
+            keep_attrs = _get_keep_attrs(default=True)
+
         dataset = {}
         for key, da in self.obj.data_vars.items():
             if self.dim in da.dims:
@@ -509,10 +531,10 @@ class Coarsen:
     DataArray.coarsen
     """
 
-    __slots__ = ("obj", "boundary", "coord_func", "windows", "side", "trim_excess")
+    __slots__ = ("obj", "boundary", "coord_func", "windows", "side", "trim_excess", "keep_attrs")
     _attributes = ("windows", "side", "trim_excess")
 
-    def __init__(self, obj, windows, boundary, side, coord_func):
+    def __init__(self, obj, windows, boundary, side, coord_func, keep_attrs):
         """
         Moving window object.
 
@@ -541,6 +563,7 @@ def __init__(self, obj, windows, boundary, side, coord_func):
         self.windows = windows
         self.side = side
         self.boundary = boundary
+        self.keep_attrs = keep_attrs
 
         absent_dims = [dim for dim in windows.keys() if dim not in self.obj.dims]
         if absent_dims:
@@ -586,7 +609,7 @@ def wrapped_func(self, **kwargs):
             from .dataarray import DataArray
 
             reduced = self.obj.variable.coarsen(
-                self.windows, func, self.boundary, self.side, **kwargs
+                self.windows, func, self.boundary, self.side, self.keep_attrs, **kwargs
             )
             coords = {}
             for c, v in self.obj.coords.items():
@@ -626,6 +649,11 @@ def _reduce_method(cls, func: Callable, include_skipna: bool, numeric_only: bool
         def wrapped_func(self, **kwargs):
             from .dataset import Dataset
 
+            if self.keep_attrs == True:
+                _attrs = self.obj.attrs
+            else:
+                attrs = {}
+
             reduced = {}
             for key, da in self.obj.data_vars.items():
                 reduced[key] = da.variable.coarsen(
@@ -644,7 +672,7 @@ def wrapped_func(self, **kwargs):
                     )
                 else:
                     coords[c] = v.variable
-            return Dataset(reduced, coords=coords)
+            return Dataset(reduced, coords=coords, attrs=attrs)
 
         return wrapped_func
 

xarray/tests/test_dataset.py

@@ -5654,6 +5654,29 @@ def test_coarsen_coords_cftime():
     np.testing.assert_array_equal(actual.time, expected_times)
 
 
+def test_coarsen_keep_attrs():
+    _attrs = {"units": "test", "long_name": "testing"}
+
+    var1 = np.linspace(10, 15, 100)
+    var2 = np.linspace(5, 10, 100)
+    coords = np.linspace(1, 10, 100)
+
+    ds = Dataset(
+        data_vars={"var1": ("coord", var1), "var2": ("coord", var2)},
+        coords={"coord": coords},
+    )
+    ds.attrs["units"] = "test"
+    ds.attrs["long_name"] = "testing"
+
+    # Test dropped attrs
+    dat = ds.coarsen(coord=5).mean()
+    assert dat.attrs == {}
+
+    # Test kept attrs
+    dat = ds.coarsen(coord=5).mean(keep_attrs=True)
+    assert dat.attrs == _attrs
+
+
 def test_rolling_properties(ds):
     # catching invalid args
     with pytest.raises(ValueError, match="exactly one dim/window should"):

xarray/tests/test_variable.py

@@ -9,7 +9,7 @@
 import pytz
 
 from xarray import Coordinate, Dataset, IndexVariable, Variable, set_options
-from xarray.core import dtypes, indexing
+from xarray.core import dtypes, duck_array_ops, indexing
 from xarray.core.common import full_like, ones_like, zeros_like
 from xarray.core.indexing import (
     BasicIndexer,
@@ -1879,6 +1879,28 @@ def test_coarsen_2d(self):
         expected = self.cls(("x", "y"), [[10, 18], [42, 35]])
         assert_equal(actual, expected)
 
+    # perhaps @pytest.mark.parametrize("operation", [f for f in duck_array_ops])
+    def test_coarsen_keep_attrs(self, operation="mean"):
+        _attrs = {"units": "test", "long_name": "testing"}
+
+        coord = Variable(["coord"], np.linspace(1, 10, 100), attrs=_attrs)
+
+        test_func = getattr(duck_array_ops, operation, None)
+
+        # Test dropped attrs
+        with set_options(keep_attrs=False):
+            new = coord.coarsen(
+                windows={"coord": 1}, func=test_func, boundary="exact", side="left"
+            )
+        assert new.attrs == {}
+
+        # Test kept attrs
+        with set_options(keep_attrs=True):
+            new = coord.coarsen(
+                windows={"coord": 1}, func=test_func, boundary="exact", side="left"
+            )
+        assert new.attrs == _attrs
+
 
 @requires_dask
 class TestVariableWithDask(VariableSubclassobjects):