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/393#issuecomment-94084387,https://api.github.com/repos/pydata/xarray/issues/393,94084387,MDEyOklzc3VlQ29tbWVudDk0MDg0Mzg3,1217238,2015-04-17T21:57:46Z,2015-04-19T00:00:56Z,MEMBER,"I would probably write a custom utility function to make the appropriate boolean vector. Something like:

``` python
def in_jjas(xray_obj):
    months = [6, 7, 8, 9]
    month_vec = xray_obj['time.month']
    result = reduce(np.logical_or, [month_vec == m for m in months])
    return result.rename('in_jjas')
```

Then you can use it like the following:

```
In [3]: ds = xray.Dataset({'time': pd.date_range('2000-01-01', periods=365)})

In [9]: in_jjas(ds)
Out[9]:
<xray.DataArray 'in_jjas' (time: 365)>
array([False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True,  True,  True,  True,  True,  True,
        True,  True,  True,  True, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False, False, False, False, False,
       False, False, False, False, False], dtype=bool)
Coordinates:
  * time     (time) datetime64[ns] 2000-01-01 2000-01-02 2000-01-03 2000-01-04 2000-01-05 ...

In [11]: ds.sel(time=in_jjas(ds))
Out[11]:
<xray.Dataset>
Dimensions:  (time: 122)
Coordinates:
  * time     (time) datetime64[ns] 2000-06-01 2000-06-02 2000-06-03 2000-06-04 2000-06-05 ...
Data variables:
    *empty*
```
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,69141510
https://github.com/pydata/xarray/issues/393#issuecomment-94132735,https://api.github.com/repos/pydata/xarray/issues/393,94132735,MDEyOklzc3VlQ29tbWVudDk0MTMyNzM1,7300413,2015-04-18T06:02:04Z,2015-04-18T06:02:04Z,NONE,"Thanks! Will extend my code in this fashion.
","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,69141510