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/1199#issuecomment-275723498,https://api.github.com/repos/pydata/xarray/issues/1199,275723498,MDEyOklzc3VlQ29tbWVudDI3NTcyMzQ5OA==,4160723,2017-01-27T17:31:01Z,2017-01-27T17:31:01Z,MEMBER,"Nice diagram! Do you think it's worth to also add `Variable` and `IndexVariable` (along with inheritance)?

Finally I would be also +1 to do nothing with the unindexed dimensions in the repr, even though complaints for large `Dataset` are valid.

Although this wouldn't fully solve the problem, maybe an html repr for the notebook would help here?
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,200125945
https://github.com/pydata/xarray/issues/1199#issuecomment-275498595,https://api.github.com/repos/pydata/xarray/issues/1199,275498595,MDEyOklzc3VlQ29tbWVudDI3NTQ5ODU5NQ==,4160723,2017-01-26T20:07:25Z,2017-01-26T21:06:22Z,MEMBER,"> We may not have gotten this right yet

I agree.

As any dimension can be indexed (at least lookup by position), the name ""coordinate"" may be indeed more appropriate, but we need also to make the distinction between coordinates which are `IndexVariable` objects and those which are `Variable` objects.

Any use case for dimensions which don't have an index (i.e., an `IndexVariable`) but have coordinates? This would be confusing too:

```
>>> xr.Dataset({'foo': (('x', 'y'), [[1, 2], [3, 4]])},
...            {'c': (('x', 'y'), [[5, 6], [7, 8]])})
<xarray.Dataset>
Dimensions:  (x: 2, y: 2)
Coordinates:
    c        (x, y) int64 5 6 7 8
Data variables:
    foo      (x, y) int64 1 2 3 4
Dimensions without coordinates: x, y
```

","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,200125945
https://github.com/pydata/xarray/issues/1199#issuecomment-275513365,https://api.github.com/repos/pydata/xarray/issues/1199,275513365,MDEyOklzc3VlQ29tbWVudDI3NTUxMzM2NQ==,4160723,2017-01-26T21:05:23Z,2017-01-26T21:05:23Z,MEMBER,"So the original issue was about highlighting in the repr which dimensions have an `IndexVariable` object and which dimensions don't.

""Dimensions without index variable"" would be unambiguous in all cases, but it doesn't look nice.

Mirroring `*` in `Dimensions` is also the less ambiguous (and most concise) of the options above, but it's not very nice too (IMHO not that ugly, though).

","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,200125945
https://github.com/pydata/xarray/issues/1199#issuecomment-272841208,https://api.github.com/repos/pydata/xarray/issues/1199,272841208,MDEyOklzc3VlQ29tbWVudDI3Mjg0MTIwOA==,4160723,2017-01-16T11:47:47Z,2017-01-16T11:47:47Z,MEMBER,"> I'm still not super happy with using o in the new repr

Yes this does not seem like the best alternative.

> after giving it a second thought: have you considered not to list the coordinates with ""o"" in the coords repr?

+1. That was the initial implementation in #1017 I think, which is the most consistent. But @crusaderky raised an issue of readability (see https://github.com/pydata/xarray/pull/1017#issuecomment-260777664).

IMO this issue of readability is more a bad habit of using the `Coordinates` section to actually inspect the dimensions (and thus not focusing enough on the `Dimensions` section), resulting from the old behavior where each dimension was guaranteed to have a (default) coordinate. Now that this is not the case anymore I wonder if new xarray users (i.e., after #1017) will encounter this issue of readability. 

If this remains an issue, another option than the ones above would be to list dimensions with no index in a separate, dedicated section of the repr, e.g. with the examples above,

```
<xarray.Dataset>
Dimensions:  (dim_0: 3)
Unindexed dimensions:
    dim_0
Data variables:
    var      (dim_0) int64 1 2 3
```

```
<xarray.DataArray 'xy' (y: 2, x: 3)>
array([[ 1.1,  2.2,  3.3],
       [ 4.4,  5.5,  6.6]])
Unindexed dimensions:
    y
Coordinates:
  * x        (x) float64 0.1 1.1 2.2
    xy       (y, x) float64 1.1 2.2 3.3 4.4 5.5 6.6
```

To not add too much verbosity, multiple dimensions without coord may be displayed inline:

```
<xarray.Dataset>
Dimensions:  (dim_0: 3, dim_1: 4)
Unindexed dimensions:
    dim_0, dim_1
Data variables:
    var      (dim_0) int64 1 2 3
```
 
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