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/pull/2968#issuecomment-498333901,https://api.github.com/repos/pydata/xarray/issues/2968,498333901,MDEyOklzc3VlQ29tbWVudDQ5ODMzMzkwMQ==,2448579,2019-06-03T16:40:46Z,2019-06-03T16:40:46Z,MEMBER,Thanks @kmsquire . The tests failed but they seem unrelated (the docs build passed).,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,445045305
https://github.com/pydata/xarray/pull/2968#issuecomment-493499465,https://api.github.com/repos/pydata/xarray/issues/2968,493499465,MDEyOklzc3VlQ29tbWVudDQ5MzQ5OTQ2NQ==,2448579,2019-05-17T15:38:59Z,2019-05-17T15:38:59Z,MEMBER,@kmsquire thanks. Can you also add some text to https://xarray.pydata.org/en/stable/computation.html#rolling-window-operations (i.e. computation.rst) describing what `min_periods` does.,"{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,445045305
https://github.com/pydata/xarray/pull/2968#issuecomment-493453581,https://api.github.com/repos/pydata/xarray/issues/2968,493453581,MDEyOklzc3VlQ29tbWVudDQ5MzQ1MzU4MQ==,10194086,2019-05-17T13:28:29Z,2019-05-17T13:28:29Z,MEMBER,"I think you can keep the function signature of `reduce` but rather allow to set  `min_periods=0` in `__init__` (This is currently disallowed on [Line 77](https://github.com/pydata/xarray/blob/master/xarray/core/rolling.py#L77)). 

Then you change your code in `reduce` to
``` python
if self.min_periods == 0:
    return result

```

btw: If I understand correctly, this does not need to be added for the other functions `ds.rolling(...).mean()` calls `reduce` on [Line 238](https://github.com/pydata/xarray/blob/master/xarray/core/rolling.py#L238).","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,445045305