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/4501#issuecomment-708588777,https://api.github.com/repos/pydata/xarray/issues/4501,708588777,MDEyOklzc3VlQ29tbWVudDcwODU4ODc3Nw==,1217238,2020-10-14T18:41:21Z,2020-10-14T18:41:32Z,MEMBER,"If we changed `isel()` to only modify data variables, then we would be in trouble with something like `isel(x=slice(3))`. The coordinate system would be inconsistent if we slice only the data variables but not the coordinates.

There's a bit of a conflict here between two desirable properties:

1. Methods on a Dataset only modify data variables, leaving coordinates unchanged
2. Methods on a Dataset keep the entire coordinate system for the Dataset consistent, including coordinates","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,718716799
https://github.com/pydata/xarray/issues/4501#issuecomment-708167473,https://api.github.com/repos/pydata/xarray/issues/4501,708167473,MDEyOklzc3VlQ29tbWVudDcwODE2NzQ3Mw==,1217238,2020-10-14T05:33:59Z,2020-10-14T05:33:59Z,MEMBER,"> What I think would be more useful:
> 
> ```
> <xarray.DataArray (x: 5)>
> array([0., 0., 0., 0., 0.])
> Coordinates:
>     y        int64 42
>     e        (y)  int64 10     <---- Note the (y)
> Dimensions without coordinates: x
> ```

Thanks for clarifying!

One problem with this -- at least for now -- is that xarray currently doesn't allow coordinates on DataArray objects to have dimensions that don't appear on the DataArray itself.

It might also be surprising that this would make `squeeze('y')` inconsistent with `isel(y=0)`","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,718716799
https://github.com/pydata/xarray/issues/4501#issuecomment-706639713,https://api.github.com/repos/pydata/xarray/issues/4501,706639713,MDEyOklzc3VlQ29tbWVudDcwNjYzOTcxMw==,1217238,2020-10-11T02:26:42Z,2020-10-11T02:26:42Z,MEMBER,"Hi @chrisroat, thanks for the clear bug report!

It indeed be nice if `squeeze` followed by `expand_dims` preserved the original inputs, but I don't think that is possible in general -- the `squeeze` operation removes information.

For example, this array *does* currently satisfy your desired property, but wouldn't if we made the change you request:
```python
arr1 = xr.DataArray(np.zeros((1,5)), dims=['y', 'x'], coords={'e': 10})
arr2 = arr1.squeeze('y').expand_dims('y')
xr.testing.assert_identical(arr1, arr2)  # passes
```

I suspect our best option for achieving this behavior would be to add another optional argument to `expand_dims`, e.g., perhaps
- `expand_dims(..., expand_coords=False)`: don't expand coordinates (default behavior)
- `expand_dims(..., expand_coords=True)`: expand all coordinates
- `expand_dims(..., expand_coords=['e'])`: only expand the coordinate `'e'`
","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,718716799