issues: 431412346

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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
431412346 MDU6SXNzdWU0MzE0MTIzNDY= 2882 Indexing with an empty sequence results in an exception 2745737 closed 0     0 2019-04-10T09:58:24Z 2019-04-12T00:25:44Z 2019-04-12T00:25:44Z CONTRIBUTOR      

Code Sample, a copy-pastable example if possible

A "Minimal, Complete and Verifiable Example" will make it much easier for maintainers to help you: http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports

```python

Your code here

da = DataArray(np.arange(12).reshape((3, 4)), dims=['x', 'y']) da[{'x': [0]}] # Okay da[{'x': []}] # error ```

Problem description

Indexing with an empty list results in an exception.

Expected Output

It should return a dataarray with an axis of length zero.

Output of xr.show_versions()

# Paste the output here xr.show_versions() here commit: 2c10d1443bea09e5ef53e5a7e35195a195e193a7 python: 3.7.3 (default, Mar 27 2019, 09:23:15) [Clang 10.0.1 (clang-1001.0.46.3)] python-bits: 64 OS: Darwin OS-release: 18.5.0 machine: x86_64 processor: i386 byteorder: little LC_ALL: en_GB.UTF-8 LANG: en_GB.UTF-8 LOCALE: en_GB.UTF-8 libhdf5: None libnetcdf: None xarray: 0.12.1+4.g2c10d144.dirty pandas: 0.24.2 numpy: 1.16.2 scipy: 1.2.1 netCDF4: None pydap: None h5netcdf: None h5py: None Nio: None zarr: None cftime: None nc_time_axis: None PseudonetCDF: None rasterio: None cfgrib: None iris: None bottleneck: 1.2.1 dask: None distributed: None matplotlib: 3.0.3 cartopy: None seaborn: None setuptools: 41.0.0 pip: 19.0.3 conda: None pytest: 4.3.1 IPython: 7.4.0 sphinx: None 
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   completed 13221727 issue

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