html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue https://github.com/pydata/xarray/issues/1931#issuecomment-367456457,https://api.github.com/repos/pydata/xarray/issues/1931,367456457,MDEyOklzc3VlQ29tbWVudDM2NzQ1NjQ1Nw==,25473287,2018-02-21T20:13:29Z,2018-02-21T20:13:29Z,NONE,"@shoyer OK, I see that keeping the core dims does make sense in some cases. I am fine with doing something like ``` xr.apply_ufunc(apply_A, dr, input_core_dims=[['x']], output_core_dims=[['x_new']]).rename({'x_new': 'x'}) ```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,298834332 https://github.com/pydata/xarray/issues/1931#issuecomment-367380855,https://api.github.com/repos/pydata/xarray/issues/1931,367380855,MDEyOklzc3VlQ29tbWVudDM2NzM4MDg1NQ==,25473287,2018-02-21T16:17:44Z,2018-02-21T16:17:44Z,NONE,"@jhamman @rabernat Thanks for the help! Raising an error when encountering this issue and adding `keep_core_coords=False` to optionally drop the coordinate would be a good solution for me. But is there any case that we do want to keep the core coordinate? Since `input_core_dims` means ""dimensions that should not be broadcast"", I suppose that the output DataArray has no way to inherit these non-broadcasting dimensions? Should the core coordinate just be dropped by default? Another more basic issue: Users are allowed the mess-up the coordinate dimension of an existing DataArray. Is this an expected behavior? ``` In [1]: import xarray as xr In [2]: xr.DataArray([0, 1, 2, 3], dims='x', coords={'x':[0, 1]}) # this is not allowed (...) ValueError: conflicting sizes for dimension 'x': length 4 on the data but length 2 on coordinate 'x' In [3]: dr = xr.DataArray([0, 1, 2, 3], dims='x', coords={'x':[0, 1, 2, 3]}) In [4]: dr['x'] = [0, 1] # but you can mess-up the coordinate dimension afterwards In [5]: dr Out[5]: <xarray.DataArray (x: 4)> array([0, 1, 2, 3]) Coordinates: * x (x) int64 0 1 In [6]: dr.to_netcdf('wrong_coordinate.nc') (...) ValueError: conflicting sizes for dimension 'x': length 4 on '__xarray_dataarray_variable__' and length 2 on 'x' ```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,298834332