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/4325#issuecomment-716399575,https://api.github.com/repos/pydata/xarray/issues/4325,716399575,MDEyOklzc3VlQ29tbWVudDcxNjM5OTU3NQ==,10194086,2020-10-26T08:40:51Z,2021-02-18T15:39:40Z,MEMBER,"This is already done for `counts`, correct? Here:

https://github.com/pydata/xarray/blob/1597e3a91eaf96626725987d23bbda2a80d2bae7/xarray/core/rolling.py#L370-L382

This should work for most of the reductions (and is a bit similar to what is done in `weighted` for `mean` and `sum`):

- [x] `count`: `isnull()` -> `rolling` -> `sum`
- [x] `argmax`: `fillna(-inf)` -> `rolling` -> `argmax`
- [x] `argmin`: `fillna(inf)` -> `rolling` -> `argmin`
- [x] `max`: `fillna(-inf)` -> `rolling` -> `max` (not sure about this one, need to be careful with the dtype)
- [x] `min`: `fillna(inf)` -> `rolling` -> `min` (dito)
- [x] `mean`: `fillna(0)` -> `rolling` -> `sum / count` (ensure nan if `count == 0`)
- [x] `prod`: `fillna(1)` -> `rolling` -> `prod`
- [x] `sum`: `fillna(0)` -> `rolling` -> `sum`
- [ ] `var`: `fillna(0)` -> `rolling` -> possible (?) but a bit more involved
- [ ] `std`: `sqrt(var)`
- [ ] `median`: probably not possible

I think this should not be too difficult, the thing is that rolling itself is already quite complicated









","{""total_count"": 2, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 2, ""rocket"": 0, ""eyes"": 0}",,675482176
https://github.com/pydata/xarray/issues/4325#issuecomment-741734592,https://api.github.com/repos/pydata/xarray/issues/4325,741734592,MDEyOklzc3VlQ29tbWVudDc0MTczNDU5Mg==,10194086,2020-12-09T12:17:15Z,2020-12-09T12:17:15Z,MEMBER,"I just saw that numpy 1.20 introduces `stride_tricks.sliding_window_view`. I have not looked at this yet. Just leaving this here for reference.

https://numpy.org/devdocs/reference/generated/numpy.lib.stride_tricks.sliding_window_view.html#numpy.lib.stride_tricks.sliding_window_view

https://numpy.org/devdocs/release/1.20.0-notes.html#sliding-window-view-provides-a-sliding-window-view-for-numpy-arrays

https://github.com/numpy/numpy/pull/17394","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,675482176