issues: 573052057

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id node_id number title user state locked assignee milestone comments created_at updated_at closed_at author_association active_lock_reason draft pull_request body reactions performed_via_github_app state_reason repo type
573052057 MDU6SXNzdWU1NzMwNTIwNTc= 3814 Allow an ellipsis in stack? 5635139 closed 0     1 2020-02-28T22:57:58Z 2020-03-19T23:19:18Z 2020-03-19T23:19:18Z MEMBER      

Could we add the ability to use an ellipsis to represent all dims in more places? For example, stack:

MCVE Code Sample

```python

In [14]: data = np.arange(15, 301, 15).reshape(2, 10)
...: da = xr.DataArray(data, dims=('y', 'x'), attrs={'test': 'test'})
...:

In [15]: da.stack(z=['x','y'])
Out[15]: <xarray.DataArray (z: 20)> array([ 15, 165, 30, 180, 45, 195, 60, 210, 75, 225, 90, 240, 105, 255, 120, 270, 135, 285, 150, 300]) Coordinates: * z (z) MultiIndex - x (z) int64 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 - y (z) int64 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Attributes: test: test

In [16]: da.stack(z=[...])

KeyError Traceback (most recent call last) <ipython-input-16-a92d0ffe931a> in <module> ----> 1 da.stack(z=[...])

~/workspace/./.venv/lib64/python3.6/site-packages/xarray/core/dataarray.py in stack(self, dimensions, dimensions_kwargs) 1739 DataArray.unstack 1740 """ -> 1741 ds = self._to_temp_dataset().stack(dimensions, dimensions_kwargs) 1742 return self._from_temp_dataset(ds) 1743

~/workspace/./.venv/lib64/python3.6/site-packages/xarray/core/dataset.py in stack(self, dimensions, **dimensions_kwargs) 3291 result = self 3292 for new_dim, dims in dimensions.items(): -> 3293 result = result._stack_once(dims, new_dim) 3294 return result 3295

~/workspace/./.venv/lib64/python3.6/site-packages/xarray/core/dataset.py in _stack_once(self, dims, new_dim) 3246 3247 # consider dropping levels that are unused? -> 3248 levels = [self.get_index(dim) for dim in dims] 3249 idx = utils.multiindex_from_product_levels(levels, names=dims) 3250 variables[new_dim] = IndexVariable(new_dim, idx)

~/workspace/./.venv/lib64/python3.6/site-packages/xarray/core/dataset.py in <listcomp>(.0) 3246 3247 # consider dropping levels that are unused? -> 3248 levels = [self.get_index(dim) for dim in dims] 3249 idx = utils.multiindex_from_product_levels(levels, names=dims) 3250 variables[new_dim] = IndexVariable(new_dim, idx)

~/workspace/./.venv/lib64/python3.6/site-packages/xarray/core/common.py in get_index(self, key) 378 """ 379 if key not in self.dims: --> 380 raise KeyError(key) 381 382 try:

KeyError: Ellipsis

```

Expected Output

Identical between ... and listing all dimensions

Output of xr.show_versions()

INSTALLED VERSIONS ------------------ commit: None python: 3.6.8 (default, Aug 7 2019, 17:28:10) python-bits: 64 OS: Linux machine: x86_64 processor: x86_64 byteorder: little LC_ALL: None LANG: en_US.utf8 LOCALE: en_US.UTF-8 libhdf5: 1.10.4 libnetcdf: None xarray: 0.15.0 pandas: 0.25.3 numpy: 1.18.1 scipy: 1.4.1 netCDF4: None pydap: None h5netcdf: None h5py: 2.10.0 Nio: None zarr: None cftime: None nc_time_axis: None PseudoNetCDF: None rasterio: None cfgrib: None iris: None bottleneck: 1.3.2 dask: 2.11.0 distributed: None matplotlib: 3.1.2 cartopy: None seaborn: 0.10.0 numbagg: None setuptools: 45.0.0 pip: 20.0.2 conda: None pytest: 5.3.2 IPython: 7.12.0 sphinx: 2.3.1 
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   completed 13221727 issue

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