issues: 312633077

Migrated from Stack Overflow.

NetCDF supports the NC_STRING type, which can stores arrays of strings in attributes. Xarray already supports reading arrays of strings from attributes in netCDF files, and It would be great if it also supported writing the same.

Reading already works

```python import xarray as xr import netCDF4 as nc

rg = nc.Dataset('test_string.nc', 'w', format='NETCDF4') rg.setncattr_string('testing', ['a', 'b']) rg.close() ds = xr.open_dataset('test_string.nc') print(ds) gives <xarray.Dataset> Dimensions: () Data variables: empty Attributes: testing: ['a', 'b'] ```

This works because I used the setncattr_string method. Setting the attributes like rg.testing = ['a', 'b'] does not work and results in a concatenated list (just like the xarray example below).

Writing doesn't work

python import xarray as xr ds = xr.Dataset() ds.attrs['testing'] = ['a', 'b'] ds.to_netcdf('asdf.nc') ds = xr.open_dataset('asdf.nc', autoclose=True) print(ds) gives <xarray.Dataset> Dimensions: () Data variables: *empty* Attributes: testing: ab

Note the list elements have been concatenated. So this is a request for xarray to implement something like netCDF4's setncattr_string. I would be happy to help do this if someone pointed me in the right direction; I looked through the code but got lost pretty quickly. Thanks.