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
607718350,MDU6SXNzdWU2MDc3MTgzNTA=,4011,missing empty group when iterate over groupby_bins,9312831,open,0,,,4,2020-04-27T17:22:31Z,2022-04-09T03:08:14Z,,NONE,,,,"When I try to iterate over the object `grouped` returned by `groupby_bins`, I found that the empty group is missing silently.  Here is a simple case:
```python
array = xr.DataArray(np.arange(4), dims='dim_0')
# one of these bins will be empty
bins = [0,4,5]
grouped = array.groupby_bins('dim_0', bins)

for i, group in enumerate(grouped):
    print(str(i)+'  '+group)
```
When a bin contains no samples (bin of (4, 5]), the empty group will be dropped.  Then how to iterate over the full bins even when some bins contain nothing?  I've read this related issue #1019. 
 But my case here need the correct order in grouped and empty groups need to be iterated over.","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/4011/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,issue