issue_comments: 1433104955

Hi @benbovy, my code works for 2 dimensions, but it doesn't with 1D. I think the error comes from .set_index(z=['across']) which delivers a "PandasIndex(Int64Index(" and not the expected "PandasIndex(MultiIndex(" for unstack.

I created a Pandas-MultiIndex "MultiIndex([((0,), (1,))], names=['z', 'across'])" (see code just below), but it is not exactly the same one as the one created by .stack() "PandasIndex(MultiIndex([(0,),(1,)], name='z'))" and I didn't find out how to pass the 'index' to xarray. python import pandas as pd tuples = [(0,),(1,)], index = pd.MultiIndex.from_tuples(tuples, names=["z","across"]) index

My modified minimal example is as below: python import xarray as xr ds = xr.Dataset( data_vars=dict( mydata = ( ['across', 'along'], [[0,1],[2,3]]) ), coords=dict( # <- changed across=[0,1], # <- changed along=[0,1], # <- changed ), # <- changed ) stacked = ds.isel(along=0).stack(z=["across"]) # <- changed newlist = [None] * stacked.z.size for ii, zindex in enumerate(stacked.z.data): newlist[ii] = stacked.mydata.sel(z=zindex) newds = xr.concat(newlist, dim='z') newds = newds.set_index(z=['across']) # <- changed newds.unstack(dim='z') # Fail with ValueError: cannot unstack dimensions that do not have exactly one multi-index: ('z',)