workaround for file with variable and dimension having same name

[johnomotani]

Adding a variable that's not a 1d "dimension coordinate" with the same name as a dimension is an error. This makes sense. However, if I have a .nc file that has such a variable, is there any workaround to get the badly-named variable into xarray short of altering the .nc file or loading it separately with netCDF4? I.e. to make the following work somehow

import xarray as xr
import netCDF4

f = netCDF4.Dataset()
f = netCDF4.Dataset("test.nc", "w")
f.createDimension("x", 2)
f.createDimension("y", 3)
f["y"] = np.ones([2,3])
f["y"][...] = 1.0
f.close()

ds = xr.open_dataset('test.nc')

rather than getting the current error MissingDimensionsError: 'y' has more than 1-dimension and the same name as one of its dimensions ('x', 'y'). xarray disallows such variables because they conflict with the coordinates used to label dimensions.

I think it might be nice to have something like a rename_vars argument to open_dataset(). Similar to how drop_vars ignores a list of variables, rename_vars could rename a dict of variables so the example above could do

ds = xr.open_dataset("test.nc", rename_vars={"y": "y_not_dimension"})

and get a Dataset with a dimension "y" and a variable "y_not_dimension".

[kmuehlbauer]

Is there any news on that topic? Has something being implemented already, to solve that issue? I'm wondering if roundtripping might be possible at all. As those files are valid nc-files, shouldn't xarray be capable of handling them?

[johnomotani]

I didn't find any solution in xarray - I think I ended up just dropping the conflicting variable...

[kmuehlbauer]

Thanks @johnomotani me neither. I wonder if xarray could just invent the same as netcdf4 did, prepending the variables internally with some prefix. But this might only get confusing.

[dcherian]

Closing as dupe of #2233. This should be fixed by the explicit indexes refactor.