issue_comments: 1450036767

Hello @TomNicholas ,

Reopening this issue 1 year later ! To answer your last question, singleton dimension seems to have, indeed, a unique behavior since they are reattached systematically to other coordinates (even if they naturally do not share any dimension with other coordinates). These singleton dimensions introduce some strange behavior. This is another example: a = xr.DataArray(np.random.rand(2,3,2), dims=('x','y','z'), coords={'x':[1,2], 'y':[3,4,5],'z':['0','1']}) b = xr.DataArray(np.random.rand(2,3,2), dims=('x','y','z'), coords={'x':[1,2], 'y':[3,4,5],'z':['0','1']}) res1 = a.sel(z='0')/b res2 = a.sel(z='0').expand_dims('z')/b res1 and res2 do not have the same size on dimension "z". In res1, dimension "z" is not considered anymore as a dimension at all !