Merge remote-tracking branch 'upstream/master' into indexes/dataarray

* upstream/master:
  Added fill_value for unstack (pydata#3541)
  Add DatasetGroupBy.quantile (pydata#3527)
  ensure rename does not change index type (pydata#3532)
  Leave empty slot when not using accessors
  interpolate_na: Add max_gap support. (pydata#3302)
  units & deprecation merge (pydata#3530)
  Fix set_index when an existing dimension becomes a level (pydata#3520)
  add Variable._replace (pydata#3528)
  Tests for module-level functions with units (pydata#3493)
  Harmonize `FillValue` and `missing_value` during encoding and decoding steps (pydata#3502)
  FUNDING.yml (pydata#3523)
  Allow appending datetime & boolean variables to zarr stores (pydata#3504)
  warn if dim is passed to rolling operations. (pydata#3513)
  Deprecate allow_lazy (pydata#3435)
  Recursive tokenization (pydata#3515)

Author: dcherian

.github/FUNDING.yml

@@ -0,0 +1,2 @@
+github: numfocus
+custom: http://numfocus.org/donate-to-xarray

doc/computation.rst

@@ -95,6 +95,9 @@ for filling missing values via 1D interpolation.
 Note that xarray slightly diverges from the pandas ``interpolate`` syntax by
 providing the ``use_coordinate`` keyword which facilitates a clear specification
 of which values to use as the index in the interpolation.
+xarray also provides the ``max_gap`` keyword argument to limit the interpolation to
+data gaps of length ``max_gap`` or smaller. See :py:meth:`~xarray.DataArray.interpolate_na`
+for more.
 
 Aggregation
 ===========

doc/conf.py

@@ -340,9 +340,10 @@
 # Example configuration for intersphinx: refer to the Python standard library.
 intersphinx_mapping = {
     "python": ("https://docs.python.org/3/", None),
-    "pandas": ("https://pandas.pydata.org/pandas-docs/stable/", None),
-    "iris": ("http://scitools.org.uk/iris/docs/latest/", None),
-    "numpy": ("https://docs.scipy.org/doc/numpy/", None),
-    "numba": ("https://numba.pydata.org/numba-doc/latest/", None),
-    "matplotlib": ("https://matplotlib.org/", None),
+    "pandas": ("https://pandas.pydata.org/pandas-docs/stable", None),
+    "iris": ("https://scitools.org.uk/iris/docs/latest", None),
+    "numpy": ("https://docs.scipy.org/doc/numpy", None),
+    "scipy": ("https://docs.scipy.org/doc/scipy/reference", None),
+    "numba": ("https://numba.pydata.org/numba-doc/latest", None),
+    "matplotlib": ("https://matplotlib.org", None),
 }

doc/whats-new.rst

@@ -38,6 +38,13 @@ Breaking changes
 
 New Features
 ~~~~~~~~~~~~
+
+- Added the ``fill_value`` option to :py:meth:`~xarray.DataArray.unstack` and
+  :py:meth:`~xarray.Dataset.unstack` (:issue:`3518`).
+  By `Keisuke Fujii <https://github.com/fujiisoup>`_.
+- Added the ``max_gap`` kwarg to :py:meth:`~xarray.DataArray.interpolate_na` and
+  :py:meth:`~xarray.Dataset.interpolate_na`. This controls the maximum size of the data
+  gap that will be filled by interpolation. By `Deepak Cherian <https://github.com/dcherian>`_.
 - :py:meth:`Dataset.drop_sel` & :py:meth:`DataArray.drop_sel` have been added for dropping labels.
   :py:meth:`Dataset.drop_vars` & :py:meth:`DataArray.drop_vars` have been added for 
   dropping variables (including coordinates). The existing ``drop`` methods remain as a backward compatible 
@@ -73,12 +80,22 @@ New Features
   for xarray objects. Note that xarray objects with a dask.array backend already used
   deterministic hashing in previous releases; this change implements it when whole
   xarray objects are embedded in a dask graph, e.g. when :meth:`DataArray.map` is
-  invoked. (:issue:`3378`, :pull:`3446`)
+  invoked. (:issue:`3378`, :pull:`3446`, :pull:`3515`)
   By `Deepak Cherian <https://github.com/dcherian>`_ and
   `Guido Imperiale <https://github.com/crusaderky>`_.
+- Add the documented-but-missing :py:meth:`xarray.core.groupby.DatasetGroupBy.quantile`.
+  (:issue:`3525`, :pull:`3527`). By `Justus Magin <https://github.com/keewis>`_.
 
 Bug fixes
 ~~~~~~~~~
+- Ensure an index of type ``CFTimeIndex`` is not converted to a ``DatetimeIndex`` when 
+  calling :py:meth:`Dataset.rename` (also :py:meth:`Dataset.rename_dims`
+  and :py:meth:`xr.Dataset.rename_vars`). By `Mathias Hauser <https://github.com/mathause>`_
+  (:issue:`3522`).
+- Fix a bug in `set_index` in case that an existing dimension becomes a level variable of MultiIndex. (:pull:`3520`)
+  By `Keisuke Fujii <https://github.com/fujiisoup>`_.
+- Harmonize `_FillValue`, `missing_value` during encoding and decoding steps. (:pull:`3502`)
+  By `Anderson Banihirwe <https://github.com/andersy005>`_. 
 - Fix regression introduced in v0.14.0 that would cause a crash if dask is installed
   but cloudpickle isn't (:issue:`3401`) by `Rhys Doyle <https://github.com/rdoyle45>`_
 - Fix grouping over variables with NaNs. (:issue:`2383`, :pull:`3406`).
@@ -88,9 +105,14 @@ Bug fixes
   By `Deepak Cherian <https://github.com/dcherian>`_.
 - Sync with cftime by removing `dayofwk=-1` for cftime>=1.0.4.
   By `Anderson Banihirwe <https://github.com/andersy005>`_.
+- Rolling reduction operations no longer compute dask arrays by default. (:issue:`3161`).
+  In addition, the ``allow_lazy`` kwarg to ``reduce`` is deprecated.
+  By `Deepak Cherian <https://github.com/dcherian>`_.
 - Fix :py:meth:`xarray.core.groupby.DataArrayGroupBy.reduce` and
   :py:meth:`xarray.core.groupby.DatasetGroupBy.reduce` when reducing over multiple dimensions.
   (:issue:`3402`). By `Deepak Cherian <https://github.com/dcherian/>`_
+- Allow appending datetime and bool data variables to zarr stores.
+  (:issue:`3480`). By `Akihiro Matsukawa <https://github.com/amatsukawa/>`_.
 
 Documentation
 ~~~~~~~~~~~~~
@@ -111,7 +133,8 @@ Internal Changes
 ~~~~~~~~~~~~~~~~
 
 - Added integration tests against `pint <https://pint.readthedocs.io/>`_.
-  (:pull:`3238`, :pull:`3447`, :pull:`3508`) by `Justus Magin <https://github.com/keewis>`_.
+  (:pull:`3238`, :pull:`3447`, :pull:`3493`, :pull:`3508`)
+  by `Justus Magin <https://github.com/keewis>`_.
 
   .. note::
 
@@ -130,6 +153,9 @@ Internal Changes
 - Enable type checking on default sentinel values (:pull:`3472`)
   By `Maximilian Roos <https://github.com/max-sixty>`_
 
+- Add :py:meth:`Variable._replace` for simpler replacing of a subset of attributes (:pull:`3472`)
+  By `Maximilian Roos <https://github.com/max-sixty>`_
+
 .. _whats-new.0.14.0:
 
 v0.14.0 (14 Oct 2019)
@@ -217,6 +243,9 @@ Bug fixes
   By `Deepak Cherian <https://github.com/dcherian>`_.
 - Fix error in concatenating unlabeled dimensions (:pull:`3362`).
   By `Deepak Cherian <https://github.com/dcherian/>`_.
+- Warn if the ``dim`` kwarg is passed to rolling operations. This is redundant since a dimension is
+  specified when the :py:class:`DatasetRolling` or :py:class:`DataArrayRolling` object is created.
+  (:pull:`3362`). By `Deepak Cherian <https://github.com/dcherian/>`_.
 
 Documentation
 ~~~~~~~~~~~~~

xarray/backends/api.py

@@ -1234,15 +1234,18 @@ def _validate_datatypes_for_zarr_append(dataset):
     def check_dtype(var):
         if (
             not np.issubdtype(var.dtype, np.number)
+            and not np.issubdtype(var.dtype, np.datetime64)
+            and not np.issubdtype(var.dtype, np.bool)
             and not coding.strings.is_unicode_dtype(var.dtype)
             and not var.dtype == object
         ):
             # and not re.match('^bytes[1-9]+$', var.dtype.name)):
             raise ValueError(
                 "Invalid dtype for data variable: {} "
                 "dtype must be a subtype of number, "
-                "a fixed sized string, a fixed size "
-                "unicode string or an object".format(var)
+                "datetime, bool, a fixed sized string, "
+                "a fixed size unicode string or an "
+                "object".format(var)
             )
 
     for k in dataset.data_vars.values():

xarray/coding/variables.py

@@ -8,7 +8,6 @@
 
 from ..core import dtypes, duck_array_ops, indexing
 from ..core.pycompat import dask_array_type
-from ..core.utils import equivalent
 from ..core.variable import Variable
 
 
@@ -152,18 +151,25 @@ def encode(self, variable, name=None):
         fv = encoding.get("_FillValue")
         mv = encoding.get("missing_value")
 
-        if fv is not None and mv is not None and not equivalent(fv, mv):
+        if (
+            fv is not None
+            and mv is not None
+            and not duck_array_ops.allclose_or_equiv(fv, mv)
+        ):
             raise ValueError(
-                "Variable {!r} has multiple fill values {}. "
-                "Cannot encode data. ".format(name, [fv, mv])
+                f"Variable {name!r} has conflicting _FillValue ({fv}) and missing_value ({mv}). Cannot encode data."
             )
 
         if fv is not None:
+            # Ensure _FillValue is cast to same dtype as data's
+            encoding["_FillValue"] = data.dtype.type(fv)
             fill_value = pop_to(encoding, attrs, "_FillValue", name=name)
             if not pd.isnull(fill_value):
                 data = duck_array_ops.fillna(data, fill_value)
 
         if mv is not None:
+            # Ensure missing_value is cast to same dtype as data's
+            encoding["missing_value"] = data.dtype.type(mv)
             fill_value = pop_to(encoding, attrs, "missing_value", name=name)
             if not pd.isnull(fill_value) and fv is None:
                 data = duck_array_ops.fillna(data, fill_value)

xarray/core/common.py

@@ -43,14 +43,12 @@ def _reduce_method(cls, func: Callable, include_skipna: bool, numeric_only: bool
         if include_skipna:
 
             def wrapped_func(self, dim=None, axis=None, skipna=None, **kwargs):
-                return self.reduce(
-                    func, dim, axis, skipna=skipna, allow_lazy=True, **kwargs
-                )
+                return self.reduce(func, dim, axis, skipna=skipna, **kwargs)
 
         else:
 
             def wrapped_func(self, dim=None, axis=None, **kwargs):  # type: ignore
-                return self.reduce(func, dim, axis, allow_lazy=True, **kwargs)
+                return self.reduce(func, dim, axis, **kwargs)
 
         return wrapped_func
 
@@ -83,20 +81,13 @@ def _reduce_method(cls, func: Callable, include_skipna: bool, numeric_only: bool
 
             def wrapped_func(self, dim=None, skipna=None, **kwargs):
                 return self.reduce(
-                    func,
-                    dim,
-                    skipna=skipna,
-                    numeric_only=numeric_only,
-                    allow_lazy=True,
-                    **kwargs,
+                    func, dim, skipna=skipna, numeric_only=numeric_only, **kwargs
                 )
 
         else:
 
             def wrapped_func(self, dim=None, **kwargs):  # type: ignore
-                return self.reduce(
-                    func, dim, numeric_only=numeric_only, allow_lazy=True, **kwargs
-                )
+                return self.reduce(func, dim, numeric_only=numeric_only, **kwargs)
 
         return wrapped_func
 

xarray/core/dataarray.py

@@ -48,7 +48,7 @@
     assert_coordinate_consistent,
     remap_label_indexers,
 )
-from .dataset import Dataset, merge_indexes, split_indexes
+from .dataset import Dataset, split_indexes
 from .formatting import format_item
 from .indexes import Indexes, copy_indexes, default_indexes
 from .merge import PANDAS_TYPES, _extract_indexes_from_coords
@@ -249,14 +249,14 @@ class DataArray(AbstractArray, DataWithCoords):
         Dictionary for holding arbitrary metadata.
     """
 
-    _accessors: Optional[Dict[str, Any]]  # noqa
+    _cache: Dict[str, Any]
     _coords: Dict[Any, Variable]
     _indexes: Optional[Dict[Hashable, pd.Index]]
     _name: Optional[Hashable]
     _variable: Variable
 
     __slots__ = (
-        "_accessors",
+        "_cache",
         "_coords",
         "_file_obj",
         "_indexes",
@@ -376,7 +376,6 @@ def __init__(
         assert isinstance(coords, dict)
         self._coords = coords
         self._name = name
-        self._accessors = None
 
         # TODO(shoyer): document this argument, once it becomes part of the
         # public interface.
@@ -772,7 +771,9 @@ def reset_coords(
             return dataset
 
     def __dask_tokenize__(self):
-        return (type(self), self._variable, self._coords, self._name)
+        from dask.base import normalize_token
+
+        return normalize_token((type(self), self._variable, self._coords, self._name))
 
     def __dask_graph__(self):
         return self._to_temp_dataset().__dask_graph__()
@@ -1617,10 +1618,10 @@ def set_index(
         --------
         DataArray.reset_index
         """
-        _check_inplace(inplace)
-        indexes = either_dict_or_kwargs(indexes, indexes_kwargs, "set_index")
-        coords, _ = merge_indexes(indexes, self._coords, set(), append=append)
-        return self._replace(coords=coords)
+        ds = self._to_temp_dataset().set_index(
+            indexes, append=append, inplace=inplace, **indexes_kwargs
+        )
+        return self._from_temp_dataset(ds)
 
     def reset_index(
         self,
@@ -1743,7 +1744,9 @@ def stack(
         return self._from_temp_dataset(ds)
 
     def unstack(
-        self, dim: Union[Hashable, Sequence[Hashable], None] = None
+        self,
+        dim: Union[Hashable, Sequence[Hashable], None] = None,
+        fill_value: Any = dtypes.NA,
     ) -> "DataArray":
         """
         Unstack existing dimensions corresponding to MultiIndexes into
@@ -1756,6 +1759,7 @@ def unstack(
         dim : hashable or sequence of hashable, optional
             Dimension(s) over which to unstack. By default unstacks all
             MultiIndexes.
+        fill_value: value to be filled. By default, np.nan
 
         Returns
         -------
@@ -1787,7 +1791,7 @@ def unstack(
         --------
         DataArray.stack
         """
-        ds = self._to_temp_dataset().unstack(dim)
+        ds = self._to_temp_dataset().unstack(dim, fill_value)
         return self._from_temp_dataset(ds)
 
     def to_unstacked_dataset(self, dim, level=0):
@@ -2034,44 +2038,69 @@ def fillna(self, value: Any) -> "DataArray":
 
     def interpolate_na(
         self,
-        dim=None,
+        dim: Hashable = None,
         method: str = "linear",
         limit: int = None,
         use_coordinate: Union[bool, str] = True,
+        max_gap: Union[int, float, str, pd.Timedelta, np.timedelta64] = None,
         **kwargs: Any,
     ) -> "DataArray":
-        """Interpolate values according to different methods.
+        """Fill in NaNs by interpolating according to different methods.
 
         Parameters
         ----------
         dim : str
             Specifies the dimension along which to interpolate.
-        method : {'linear', 'nearest', 'zero', 'slinear', 'quadratic', 'cubic',
-                  'polynomial', 'barycentric', 'krog', 'pchip',
-                  'spline', 'akima'}, optional
+        method : str, optional
             String indicating which method to use for interpolation:
 
             - 'linear': linear interpolation (Default). Additional keyword
-              arguments are passed to ``numpy.interp``
-            - 'nearest', 'zero', 'slinear', 'quadratic', 'cubic',
-              'polynomial': are passed to ``scipy.interpolate.interp1d``. If
-              method=='polynomial', the ``order`` keyword argument must also be
+              arguments are passed to :py:func:`numpy.interp`
+            - 'nearest', 'zero', 'slinear', 'quadratic', 'cubic', 'polynomial':
+              are passed to :py:func:`scipy.interpolate.interp1d`. If
+              ``method='polynomial'``, the ``order`` keyword argument must also be
               provided.
-            - 'barycentric', 'krog', 'pchip', 'spline', and `akima`: use their
-              respective``scipy.interpolate`` classes.
-        use_coordinate : boolean or str, default True
+            - 'barycentric', 'krog', 'pchip', 'spline', 'akima': use their
+              respective :py:class:`scipy.interpolate` classes.
+        use_coordinate : bool, str, default True
             Specifies which index to use as the x values in the interpolation
             formulated as `y = f(x)`. If False, values are treated as if
-            eqaully-spaced along `dim`. If True, the IndexVariable `dim` is
-            used. If use_coordinate is a string, it specifies the name of a
+            eqaully-spaced along ``dim``. If True, the IndexVariable `dim` is
+            used. If ``use_coordinate`` is a string, it specifies the name of a
             coordinate variariable to use as the index.
         limit : int, default None
             Maximum number of consecutive NaNs to fill. Must be greater than 0
-            or None for no limit.
+            or None for no limit. This filling is done regardless of the size of
+            the gap in the data. To only interpolate over gaps less than a given length,
+            see ``max_gap``.
+        max_gap: int, float, str, pandas.Timedelta, numpy.timedelta64, default None.
+            Maximum size of gap, a continuous sequence of NaNs, that will be filled.
+            Use None for no limit. When interpolating along a datetime64 dimension
+            and ``use_coordinate=True``, ``max_gap`` can be one of the following:
+
+            - a string that is valid input for pandas.to_timedelta
+            - a :py:class:`numpy.timedelta64` object
+            - a :py:class:`pandas.Timedelta` object
+            Otherwise, ``max_gap`` must be an int or a float. Use of ``max_gap`` with unlabeled
+            dimensions has not been implemented yet. Gap length is defined as the difference
+            between coordinate values at the first data point after a gap and the last value
+            before a gap. For gaps at the beginning (end), gap length is defined as the difference
+            between coordinate values at the first (last) valid data point and the first (last) NaN.
+            For example, consider::
+
+                <xarray.DataArray (x: 9)>
+                array([nan, nan, nan,  1., nan, nan,  4., nan, nan])
+                Coordinates:
+                  * x        (x) int64 0 1 2 3 4 5 6 7 8
+
+            The gap lengths are 3-0 = 3; 6-3 = 3; and 8-6 = 2 respectively
+        kwargs : dict, optional
+            parameters passed verbatim to the underlying interpolation function
 
         Returns
         -------
-        DataArray
+        interpolated: DataArray
+            Filled in DataArray.
 
         See also
         --------
@@ -2086,6 +2115,7 @@ def interpolate_na(
             method=method,
             limit=limit,
             use_coordinate=use_coordinate,
+            max_gap=max_gap,
             **kwargs,
         )