id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
498365185,MDExOlB1bGxSZXF1ZXN0MzIxMzExMzE3,3344,groupby repr,2448579,closed,0,,,4,2019-09-25T15:34:33Z,2019-10-03T16:12:23Z,2019-10-03T15:41:50Z,MEMBER,,0,pydata/xarray/pulls/3344,"Adds a simple groupby repr. Feedback appreciated

```
da = xr.DataArray(
    np.random.randn(10, 20, 6),
    dims=[""x"", ""y"", ""z""],
    coords={""z"": [""a"", ""b"", ""c"", ""a"", ""b"", ""c""], 
            ""x"": [1, 1, 1, 2, 2, 3, 4, 5, 3, 4]},
)
```

``` da.groupby(""x"")
DataArrayGroupBy, grouped over 'x' 
5 groups with labels 1, 2, 3, 4, 5
```
```da.groupby(""y"")
DataArrayGroupBy, grouped over 'y' 
20 groups with labels 0, 1, 2, 3, 4, 5, ..., 15, 16, 17, 18, 19
```
```
da.groupby(""z"")
DataArrayGroupBy, grouped over 'z' 
6 groups with labels 'a', 'b', 'c', 'd', 'e', 'f'
```

 - [x] Tests added
 - [x] Passes `black . && mypy . && flake8`
 - [x] Fully documented, including `whats-new.rst` for all changes and `api.rst` for new API
","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/3344/reactions"", ""total_count"": 1, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 1, ""rocket"": 0, ""eyes"": 0}",,,13221727,pull