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/2944#issuecomment-540182562,https://api.github.com/repos/pydata/xarray/issues/2944,540182562,MDEyOklzc3VlQ29tbWVudDU0MDE4MjU2Mg==,2448579,2019-10-09T20:36:55Z,2019-10-09T20:36:55Z,MEMBER,"So that has been fixed on master somehow but

``` python
da = xr.DataArray(np.arange(12).reshape(3, 4), dims=['x', 'y'],
                  coords={'x': [0, 1, 1], 
                          'x2': ('x', ['a', 'b', 'c']),
                          'x3': ('x', [4, 5, 6])})
da.groupby(""x"").mean(""x"")
```
gives
```
<xarray.DataArray (x: 2, y: 4)>
array([[0., 1., 2., 3.],
       [6., 7., 8., 9.]])
Coordinates:
  * x        (x) int64 0 1
Dimensions without coordinates: y
```

i.e coordinate `x3` has been dropped though the mean along `x` is meaningful. This is consistent with the behaviour of `reduce` e.g.
``` python
da.mean(""x"")

<xarray.DataArray (y: 4)>
array([4., 5., 6., 7.])
Dimensions without coordinates: y
```

What would be the best way to implement reductions for non-dim coords? Add a `reduce_coords` kwarg?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,441088452