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/3438#issuecomment-567300564,https://api.github.com/repos/pydata/xarray/issues/3438,567300564,MDEyOklzc3VlQ29tbWVudDU2NzMwMDU2NA==,1217238,2019-12-19T02:19:21Z,2019-12-19T02:19:21Z,MEMBER,"> However, I would argue that `rename_dims` should raise an error if a new dimension already exists (and maybe point to `swap_dims`).

+1 this sounds like a good idea","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,511498714
https://github.com/pydata/xarray/issues/3438#issuecomment-545590827,https://api.github.com/repos/pydata/xarray/issues/3438,545590827,MDEyOklzc3VlQ29tbWVudDU0NTU5MDgyNw==,14808389,2019-10-23T19:05:18Z,2019-10-23T19:05:18Z,MEMBER,"I don't know whether that is intended or not, but I think that the operation of replacing `observations` with `individuals` is better done with `swap_dims`:
```python
>>> xr.__version__
'0.14.0'
>>> ds.rename_dims(observations=""individuals"").stack(observations=[""individuals"", ""genes""])
<xarray.Dataset>
Dimensions:       (observations: 4, subtissues: 2)
Coordinates:
  * observations  (observations) MultiIndex
  - individuals   (observations) int64 0 0 1 1
  - genes         (observations) object 'a' 'b' 'a' 'b'
  * subtissues    (subtissues) <U1 'c' 'd'
Data variables:
    test          (subtissues, observations) int64 1 1 3 3 2 2 4 4
>>> ds.swap_dims({""observations"": ""individuals""}).stack(observations=[""individuals"", ""genes""])
<xarray.Dataset>
Dimensions:       (observations: 4, subtissues: 2)
Coordinates:
  * observations  (observations) MultiIndex
  - individuals   (observations) object 'x' 'x' 'y' 'y'
  - genes         (observations) object 'a' 'b' 'a' 'b'
  * subtissues    (subtissues) <U1 'c' 'd'
Data variables:
    test          (subtissues, observations) int64 1 1 3 3 2 2 4 4
```
Indeed it seems that on 0.13.0 using `rename_dims` worked, so that would be a regression. However, I would argue that `rename_dims` should raise an error if a new dimension already exists (and maybe point to `swap_dims`).","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,511498714