issues: 1233594189

What happened?

xr.where() used to change the values between 0 or 1 in a dataset/dataArray given a condition. xr.set_options(keep_attrs=True) to keep attributes on xarray Datasets/dataarrays after operations.

xr. where() failed

What did you expect to happen?

No response

Minimal Complete Verifiable Example

```Python import numpy as np import xarray as xr x = xr.DataArray(

0.1 * np.arange(10),
dims=["lat"],
coords={"lat": np.arange(10)},
name="sst",

) x <xarray.DataArray 'sst' (lat: 10)> array([0. , 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9]) Coordinates: * lat (lat) int64 0 1 2 3 4 5 6 7 8 9 xr.where((x < 0.5), 0, 1) <xarray.DataArray 'sst' (lat: 10)> array([0, 0, 0, 0, 0, 1, 1, 1, 1, 1]) Coordinates: * lat (lat) int64 0 1 2 3 4 5 6 7 8 9 xr.set_options(keep_attrs=True) <xarray.core.options.set_options object at 0x7f7c5bb12f10> xr.where((x < 0.5), 0, 1) Traceback (most recent call last): File "/home/cuadradot/miniconda3/envs/metro_validation/lib/python3.9/code.py", line 90, in runcode exec(code, self.locals) File "", line 1, in <module> File "/home/cuadradot/miniconda3/envs/metro_validation/lib/python3.9/site-packages/xarray/core/computation.py", line 1815, in where return apply_ufunc( File "/home/cuadradot/miniconda3/envs/metro_validation/lib/python3.9/site-packages/xarray/core/computation.py", line 1159, in apply_ufunc return apply_dataarray_vfunc( File "/home/cuadradot/miniconda3/envs/metro_validation/lib/python3.9/site-packages/xarray/core/computation.py", line 286, in apply_dataarray_vfunc result_var = func(*data_vars) File "/home/cuadradot/miniconda3/envs/metro_validation/lib/python3.9/site-packages/xarray/core/computation.py", line 743, in apply_variable_ufunc attrs = merge_attrs( File "/home/cuadradot/miniconda3/envs/metro_validation/lib/python3.9/site-packages/xarray/core/merge.py", line 518, in merge_attrs return combine_attrs(variable_attrs, context=context) File "/home/cuadradot/miniconda3/envs/metro_validation/lib/python3.9/site-packages/xarray/core/computation.py", line 1812, in <lambda> keep_attrs = lambda attrs, context: attrs[1] IndexError: list index out of range ```

MVCE confirmation

• [X] Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray.
• [X] Complete example — the example is self-contained, including all data and the text of any traceback.
• [X] Verifiable example — the example copy & pastes into an IPython prompt or Binder notebook, returning the result.
• [X] New issue — a search of GitHub Issues suggests this is not a duplicate.

Relevant log output

No response

Anything else we need to know?

No response

Environment

commit: None python: 3.9.12 | packaged by conda-forge | (main, Mar 24 2022, 23:22:55) [GCC 10.3.0] python-bits: 64 OS: Linux OS-release: 5.13.0-27-generic machine: x86_64 processor: x86_64 byteorder: little LC_ALL: None LANG: en_US.UTF-8 LOCALE: ('en_US', 'UTF-8') libhdf5: 1.12.1 libnetcdf: 4.8.1 xarray: 2022.3.0 pandas: 1.4.2 numpy: 1.22.3 scipy: 1.8.0 netCDF4: 1.5.8 pydap: None h5netcdf: None h5py: None Nio: None zarr: None cftime: 1.6.0 nc_time_axis: None PseudoNetCDF: None rasterio: None cfgrib: None iris: None bottleneck: 1.3.4 dask: 2022.04.1 distributed: 2022.4.1 matplotlib: 3.5.1 cartopy: 0.20.2 seaborn: 0.11.2 numbagg: None fsspec: 2022.3.0 cupy: None pint: None sparse: 0.13.0 setuptools: 62.1.0 pip: 22.0.4 conda: None pytest: None IPython: None sphinx: None