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/1050#issuecomment-670971584,https://api.github.com/repos/pydata/xarray/issues/1050,670971584,MDEyOklzc3VlQ29tbWVudDY3MDk3MTU4NA==,8833517,2020-08-08T20:39:11Z,2020-08-08T20:39:11Z,CONTRIBUTOR,"In [`core/nanops.py`](https://github.com/pydata/xarray/blob/master/xarray/core/nanops.py) there are some explicit defaults of `ddof=0` within xarray, but I'm not sure if those are always used or if there are also cases where `var` (or `std`) are directly passed on to numpy/bottleneck/dask.

I'm considering two different options to clarify this:

1. Add a docstring section on the `ddof` parameter specifying it uses `ddof=0` as default for the reduction methods that use it, i.e. `var` and `std`. Possibly just copied from numpy's [`var`](https://numpy.org/doc/stable/reference/generated/numpy.var.html) page.
2. Refer to numpy's documentation page in the docstring of all reduction methods for further reference.

Both would require some logic in [`core/ops.py`](https://github.com/pydata/xarray/blob/master/xarray/core/ops.py): either to check for which reduce methods need a `ddof` paragraph, or to create the proper url (which has to adjust `min` and `max` to `np.amin` and `np.amax` respectively)

Is there any clear preference from anyone about this?","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,183713222