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https://github.com/pydata/xarray/issues/2436#issuecomment-610020749 https://api.github.com/repos/pydata/xarray/issues/2436 610020749 MDEyOklzc3VlQ29tbWVudDYxMDAyMDc0OQ== 16655388 2020-04-06T20:31:10Z 2020-04-06T20:31:10Z NONE

3498 added a new keyword argument to open_mfdataset, to choose which file to load to attributes from, can you try using that?

3498 says something about a master_file keyword but xr.open_mfdataset does not accept it and I do not see anything else similar in the documentation except attrs_file but it is the first file by default and it did not return the calendar even when I specified attrs_file=l_f[0].

If this is the case, then to solve your original problem, you could also try using the preprocess argument to open_mfdataset to store the encoding somewhere where it won't be lost? i.e.

```python def store_encoding(ds): encoding = ds['time'].encoding ds.time.attrs['calendar_encoding'] = encoding return ds

snw = xr.open_mfdataset(l_f, combine='nested', concat_dim='time', master_file=lf[0], preprocess=store_encoding)['snw'] ```

I tried and it did not work ... ipdb> ds = xr.open_mfdataset(l_f, combine='nested', concat_dim='time', preprocess=store_encoding) ipdb> ds.time <xarray.DataArray 'time' (time: 2920)> array([cftime.DatetimeNoLeap(2006-01-01 00:00:00), cftime.DatetimeNoLeap(2006-01-01 03:00:00), cftime.DatetimeNoLeap(2006-01-01 06:00:00), ..., cftime.DatetimeNoLeap(2006-12-31 15:00:00), cftime.DatetimeNoLeap(2006-12-31 18:00:00), cftime.DatetimeNoLeap(2006-12-31 21:00:00)], dtype=object) Coordinates: * time (time) object 2006-01-01 00:00:00 ... 2006-12-31 21:00:00 Attributes: long_name: time standard_name: time axis: T coordinate_defines: point ipdb> ds.time.attrs {'long_name': 'time', 'standard_name': 'time', 'axis': 'T', 'coordinate_defines': 'point'}

Related question but maybe out of line, is there any way to know that the snw.time type is cftime.DatetimeNoLeap (as it is visible in the overview of snw.time)?

I'm not familiar with these classes, but presumably you mean more than just checking with isinstance()? e.g.

Yes, I was more thinking of something like type(ds.time) which would return cftime.DatetimeNoLeap

python from cftime import DatetimeNoLeap print(isinstance(snw.time.values, cftime.DatetimeNoLeap))

 
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