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/2770#issuecomment-464190675,https://api.github.com/repos/pydata/xarray/issues/2770,464190675,MDEyOklzc3VlQ29tbWVudDQ2NDE5MDY3NQ==,2448579,2019-02-15T20:37:34Z,2019-02-15T20:37:34Z,MEMBER,Though for datetime64 we should use ~np.nat?,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,409906674
https://github.com/pydata/xarray/issues/2770#issuecomment-464189040,https://api.github.com/repos/pydata/xarray/issues/2770,464189040,MDEyOklzc3VlQ29tbWVudDQ2NDE4OTA0MA==,1217238,2019-02-15T20:31:15Z,2019-02-15T20:31:15Z,MEMBER,"Apparently `isnull(datetime64_scalar_array)` returns a Python boolean `False`. This gets inverted by `~` to `-1` instead of `True` in our implementation of count:
https://github.com/pydata/xarray/blob/4cd56a9edb083a3eb8d11e7a367dfb9bda76fc2e/xarray/core/duck_array_ops.py#L188

To fix this, we should either switch `~x` to `np.logical_not(x)`.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,409906674
https://github.com/pydata/xarray/issues/2770#issuecomment-464188585,https://api.github.com/repos/pydata/xarray/issues/2770,464188585,MDEyOklzc3VlQ29tbWVudDQ2NDE4ODU4NQ==,1217238,2019-02-15T20:29:25Z,2019-02-15T20:29:25Z,MEMBER,"The problem seems to come up for scalar `datetime64` arrays:
```
>>> xarray.Variable((), np.datetime64('2000-01-01')).count()
-1
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,409906674
https://github.com/pydata/xarray/issues/2770#issuecomment-464088384,https://api.github.com/repos/pydata/xarray/issues/2770,464088384,MDEyOklzc3VlQ29tbWVudDQ2NDA4ODM4NA==,5852283,2019-02-15T15:22:48Z,2019-02-15T15:22:48Z,CONTRIBUTOR,"I can reproduce OP when the coordinate is a datetime64, but the problem does not occur with int64s (or float64s). 

datetime coordinate:
```
In [1]: import xarray

In [2]: xarray.__version__
Out[2]: '0.11.2'

In [3]: import datetime as dt

In [4]: da = xarray.DataArray([0], coords=[('time', [dt.datetime(1979, 1, 1)])])

In [5]: da.isel(time=0).time.count()
Out[5]:
<xarray.DataArray 'time' ()>
array(-1)
Coordinates:
    time     datetime64[ns] 1979-01-01
```

int coordinate:

```
In [6]: da = xarray.DataArray([0], coords=[('time', [0])])

In [7]: da.isel(time=0).time.count()
Out[7]:
<xarray.DataArray 'time' ()>
array(1)
Coordinates:
    time     int64 0
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,409906674
https://github.com/pydata/xarray/issues/2770#issuecomment-463327251,https://api.github.com/repos/pydata/xarray/issues/2770,463327251,MDEyOklzc3VlQ29tbWVudDQ2MzMyNzI1MQ==,5635139,2019-02-13T19:10:38Z,2019-02-13T19:10:38Z,MEMBER,"Thanks for the issue @ru111 

That does seem weird. Do you have a minimally reproducible example?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,409906674