Merge remote-tracking branch 'upstream/master' into dask-tokenize

* upstream/master:
  upgrade black verison to 19.10b0 (pydata#3456)
  Remove outdated code related to compatibility with netcdftime (pydata#3450)
  Remove deprecated behavior from dataset.drop docstring (pydata#3451)
  jupyterlab dark theme (pydata#3443)
  Drop groups associated with nans in group variable (pydata#3406)
  Allow ellipsis (...) in transpose (pydata#3421)
  Another groupby.reduce bugfix. (pydata#3403)
  add icomoon license (pydata#3448)
  change ALL_DIMS to equal ellipsis (pydata#3418)
  Escaping dtypes (pydata#3444)
  Html repr (pydata#3425)

Author: dcherian

MANIFEST.in

@@ -6,3 +6,4 @@ prune doc/generated
 global-exclude .DS_Store
 include versioneer.py
 include xarray/_version.py
+recursive-include xarray/static *

README.rst

@@ -138,4 +138,7 @@ under a "3-clause BSD" license:
 xarray also bundles portions of CPython, which is available under the "Python
 Software Foundation License" in xarray/core/pycompat.py.
 
+xarray uses icons from the icomoon package (free version), which is
+available under the "CC BY 4.0" license.
+
 The full text of these licenses are included in the licenses directory.

doc/examples/multidimensional-coords.rst

@@ -107,7 +107,7 @@ function to specify the output coordinates of the group.
     lat_center = np.arange(1, 90, 2)
     # group according to those bins and take the mean
     Tair_lat_mean = (ds.Tair.groupby_bins('xc', lat_bins, labels=lat_center)
-	             .mean(xr.ALL_DIMS))
+	             .mean(...))
     # plot the result
     @savefig xarray_multidimensional_coords_14_1.png width=5in
     Tair_lat_mean.plot();

doc/groupby.rst

@@ -116,7 +116,13 @@ dimensions *other than* the provided one:
 
 .. ipython:: python
 
-    ds.groupby('x').std(xr.ALL_DIMS)
+    ds.groupby('x').std(...)
+
+.. note::
+
+    We use an ellipsis (`...`) here to indicate we want to reduce over all
+    other dimensions  
+
 
 First and last
 ~~~~~~~~~~~~~~
@@ -127,7 +133,7 @@ values for group along the grouped dimension:
 
 .. ipython:: python
 
-    ds.groupby('letters').first(xr.ALL_DIMS)
+    ds.groupby('letters').first(...)
 
 By default, they skip missing values (control this with ``skipna``).
 
@@ -142,7 +148,7 @@ coordinates. For example:
 
 .. ipython:: python
 
-    alt = arr.groupby('letters').mean(xr.ALL_DIMS)
+    alt = arr.groupby('letters').mean(...)
     alt
     ds.groupby('letters') - alt
 
@@ -195,7 +201,7 @@ __ http://cfconventions.org/cf-conventions/v1.6.0/cf-conventions.html#_two_dimen
                 'lat': (['ny','nx'], [[10,10],[20,20]] ),},
         dims=['ny','nx'])
     da
-    da.groupby('lon').sum(xr.ALL_DIMS)
+    da.groupby('lon').sum(...)
     da.groupby('lon').apply(lambda x: x - x.mean(), shortcut=False)
 
 Because multidimensional groups have the ability to generate a very large
@@ -213,4 +219,4 @@ applying your function, and then unstacking the result:
 .. ipython:: python
 
    stacked = da.stack(gridcell=['ny', 'nx'])
-   stacked.groupby('gridcell').sum(xr.ALL_DIMS).unstack('gridcell')
+   stacked.groupby('gridcell').sum(...).unstack('gridcell')

doc/reshaping.rst

@@ -18,12 +18,14 @@ Reordering dimensions
 ---------------------
 
 To reorder dimensions on a :py:class:`~xarray.DataArray` or across all variables
-on a :py:class:`~xarray.Dataset`, use :py:meth:`~xarray.DataArray.transpose`:
+on a :py:class:`~xarray.Dataset`, use :py:meth:`~xarray.DataArray.transpose`. An 
+ellipsis (`...`) can be use to represent all other dimensions:
 
 .. ipython:: python
 
     ds = xr.Dataset({'foo': (('x', 'y', 'z'), [[[42]]]), 'bar': (('y', 'z'), [[24]])})
     ds.transpose('y', 'z', 'x')
+    ds.transpose(..., 'x')  # equivalent
     ds.transpose()  # reverses all dimensions
 
 Expand and squeeze dimensions

doc/whats-new.rst

@@ -22,9 +22,23 @@ Breaking changes
 ~~~~~~~~~~~~~~~~
 
 - Minimum cftime version is now 1.0.3. By `Deepak Cherian <https://github.com/dcherian>`_.
+- All leftover support for dates from non-standard calendars through netcdftime, the
+  module included in versions of netCDF4 prior to 1.4 that eventually became the
+  cftime package, has been removed in favor of relying solely on the standalone
+  cftime package (:pull:`3450`).  By `Spencer Clark 
+  <https://github.com/spencerkclark>`_. 
 
 New Features
 ~~~~~~~~~~~~
+- :py:meth:`Dataset.transpose` and :py:meth:`DataArray.transpose` now support an ellipsis (`...`)
+  to represent all 'other' dimensions. For example, to move one dimension to the front,
+  use `.transpose('x', ...)`. (:pull:`3421`)
+  By `Maximilian Roos <https://github.com/max-sixty>`_
+- Changed `xr.ALL_DIMS` to equal python's `Ellipsis` (`...`), and changed internal usages to use
+  `...` directly. As before, you can use this to instruct a `groupby` operation
+  to reduce over all dimensions. While we have no plans to remove `xr.ALL_DIMS`, we suggest
+  using `...`.
+  By `Maximilian Roos <https://github.com/max-sixty>`_
 - Added integration tests against `pint <https://pint.readthedocs.io/>`_.
   (:pull:`3238`) by `Justus Magin <https://github.com/keewis>`_.
 
@@ -36,14 +50,23 @@ New Features
     ``pip install git+https://github.com/andrewgsavage/pint.git@refs/pull/6/head)``.
     Even with it, interaction with non-numpy array libraries, e.g. dask or sparse, is broken.
 
+- Added new :py:meth:`Dataset._repr_html_` and :py:meth:`DataArray._repr_html_` to improve
+  representation of objects in jupyter. By default this feature is turned off
+  for now. Enable it with :py:meth:`xarray.set_options(display_style="html")`.
+  (:pull:`3425`) by `Benoit Bovy <https://github.com/benbovy>`_ and
+  `Julia Signell <https://github.com/jsignell>`_.
+
 Bug fixes
 ~~~~~~~~~
 - 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>`_
-
-- Sync with cftime by removing `dayofwk=-1` for cftime>=1.0.4. 
+- Fix grouping over variables with NaNs. (:issue:`2383`, :pull:`3406`).
+  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>`_.
-
+- 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/>`_
 
 Documentation
 ~~~~~~~~~~~~~