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/3537#issuecomment-554958463,https://api.github.com/repos/pydata/xarray/issues/3537,554958463,MDEyOklzc3VlQ29tbWVudDU1NDk1ODQ2Mw==,24736507,2019-11-18T10:39:56Z,2019-11-19T09:23:14Z,NONE,"Hello @crusaderky! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:
There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers:
##### Comment last updated at 2019-11-19 09:23:14 UTC","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554980232,https://api.github.com/repos/pydata/xarray/issues/3537,554980232,MDEyOklzc3VlQ29tbWVudDU1NDk4MDIzMg==,6213168,2019-11-18T11:42:16Z,2019-11-18T11:42:16Z,MEMBER,Ready for review and merge,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554980168,https://api.github.com/repos/pydata/xarray/issues/3537,554980168,MDEyOklzc3VlQ29tbWVudDU1NDk4MDE2OA==,6213168,2019-11-18T11:42:04Z,2019-11-18T11:42:04Z,MEMBER,"``datetime_to_numeric(offset=None)`` never worked with dask to begin with - there's a big fat TODO in it about it. I rewrote most of the PR; now mean() works with dask.
Pre-empting an observation: *yes*, the nanmin function I wrote *could* be used to work around the shortcomings of both numpy and dask on datetime64. I don't think xarray should do it and IMHO the workaround currently implemented for mean() should never have been done to begin with.
Again, this PR only fixes the regression on numpy 1.18.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554495070,https://api.github.com/repos/pydata/xarray/issues/3537,554495070,MDEyOklzc3VlQ29tbWVudDU1NDQ5NTA3MA==,6213168,2019-11-15T19:25:48Z,2019-11-15T19:25:48Z,MEMBER, I just realised there are no tests at all for ``datetime_to_numeric(offset=None) `` on a dask backend. I suspect I broke something - I need to look at it better. ,"{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554457858,https://api.github.com/repos/pydata/xarray/issues/3537,554457858,MDEyOklzc3VlQ29tbWVudDU1NDQ1Nzg1OA==,221526,2019-11-15T17:41:52Z,2019-11-15T19:02:03Z,CONTRIBUTOR,"IMO, it's always best to release code that you *know* will work rather than rely on upstream to get something into the next release in order for you not to be broken. I say that both as a downstream user of xarray and a library maintainer.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554485869,https://api.github.com/repos/pydata/xarray/issues/3537,554485869,MDEyOklzc3VlQ29tbWVudDU1NDQ4NTg2OQ==,6213168,2019-11-15T18:58:24Z,2019-11-15T19:00:46Z,MEMBER,"Updated PR description:
Fix mean() and nanmean() for datetime64 arrays on numpy backend when upgrading from numpy 1.17 to 1.18.
All other nan-reductions on datetime64s were broken before and remain broken.
mean() on datetime64 and dask was broken before and remains broken.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554485350,https://api.github.com/repos/pydata/xarray/issues/3537,554485350,MDEyOklzc3VlQ29tbWVudDU1NDQ4NTM1MA==,10194086,2019-11-15T18:57:01Z,2019-11-15T18:57:01Z,MEMBER,"Ok, thanks for the clarification. ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554483242,https://api.github.com/repos/pydata/xarray/issues/3537,554483242,MDEyOklzc3VlQ29tbWVudDU1NDQ4MzI0Mg==,5635139,2019-11-15T18:51:14Z,2019-11-15T18:51:14Z,MEMBER,Agree—let's merge?,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554481913,https://api.github.com/repos/pydata/xarray/issues/3537,554481913,MDEyOklzc3VlQ29tbWVudDU1NDQ4MTkxMw==,6213168,2019-11-15T18:47:21Z,2019-11-15T18:50:38Z,MEMBER,"@dopplershift fully agree.
> is this the only place of min for datetimes?
This PR *does not* fix the nan-reductions for datetime arrays.
It *very narrowly* fixes the use case of **mean() and nanmean() with a numpy backend**, so that they work on numpy 1.18 as they did on 1.17. As a matter of fact they never worked with dask, were never tested, and still won't work after the PR.
To emphasize: I am not introducing any new feature or fixing bugs on numpy 1.17; I'm just getting rid of regressions on the upgrade from 1.17 to 1.18.
Specifically, the PR fixes this failing test:
https://github.com/pydata/xarray/blob/aa876cfd6b3b97ee5028d089ec741d057e3ed688/xarray/tests/test_duck_array_ops.py#L276-L293
which was not well formulated - despite its name, it doesn't test all reductions, only mean(), and in fact never runs on dask (the index of a dask array is not chunked).
I have now rewritten it for the sake of clarity.
*If* numpy/numpy#14841 makes into master before 1.18 is published, and *if* it actually delivers on making reductions work with NaT (I did not test it yet), I'll be happy to write a second PR and rework everything.
Even then, a switch of this sort will still be needed:
```python
def datetime_nanmin(array, **kwargs):
if LooseVersion(numpy.__version__) < ""1.18"":
return np.min(array, **kwargs)
else:
return np.nanmin(array, **kwargs)
```
The actual code will be in fact more complicated because you also need to think about dask.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554479623,https://api.github.com/repos/pydata/xarray/issues/3537,554479623,MDEyOklzc3VlQ29tbWVudDU1NDQ3OTYyMw==,2448579,2019-11-15T18:40:53Z,2019-11-15T18:40:53Z,MEMBER,LGTM. I think we should merge so we can get a release out.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554355882,https://api.github.com/repos/pydata/xarray/issues/3537,554355882,MDEyOklzc3VlQ29tbWVudDU1NDM1NTg4Mg==,10194086,2019-11-15T13:20:16Z,2019-11-15T13:20:16Z,MEMBER,"Given https://github.com/numpy/numpy/pull/14841 - is this worth the extra complexity?
Currently xarray is only broken wrt numpy master and there is a chance https://github.com/numpy/numpy/pull/14841 gets into 1.18 - then we could just use `np.nanmin`?
Also - is this the only place of `min` for datetimes? Should this also go into the operator dispatcher?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554352386,https://api.github.com/repos/pydata/xarray/issues/3537,554352386,MDEyOklzc3VlQ29tbWVudDU1NDM1MjM4Ng==,6213168,2019-11-15T13:08:25Z,2019-11-15T13:08:25Z,MEMBER,Ready for review and merge,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384
https://github.com/pydata/xarray/pull/3537#issuecomment-554341027,https://api.github.com/repos/pydata/xarray/issues/3537,554341027,MDEyOklzc3VlQ29tbWVudDU1NDM0MTAyNw==,6213168,2019-11-15T12:26:50Z,2019-11-15T12:26:50Z,MEMBER,xref #3434,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,523438384