issue_comments: 610053703

unfortunately, numpy does not allow us to put cftime object into dtypes (yet!), so ds.time.values is a numpy.ndarray with dtype object, containing cftime objects. To make the code work, use it with ds.time.values[0]. Of course, that won't help if the array contains objects of more than one type.

```python

import cftime isinstance(ds.time.values[0], cftime.DatetimeNoLeap) True type(ds.time.values[0]) <class 'cftime._cftime.DatetimeNoLeap'> ```

In #3498, the original proposal was to name the new kwarg master_file, but later it was renamed to attrs_file. If l_f is a list of file paths, you used it correctly.

Before trying to help with debugging your issue: could you post the output of xr.show_versions()? That would help narrowing down on whether it's a dependency issue or a bug in xarray.

Also, could you try to demonstrate your issue using a synthetic example? I've been trying to reproduce it with: python In [14]: units = 'days since 2000-02-25' ...: times = cftime.num2date(np.arange(7), units=units, calendar='365_day') ...: for x in range(5): ...: ds = xr.DataArray( ...: np.arange(x, 7 + x).reshape(7, 1), ...: coords={"time": times, "x": [x]}, ...: dims=['time', "x"], ...: name='a', ...: ).to_dataset() ...: ds.to_netcdf(f'data-noleap{x}.nc') ...: paths = sorted(glob.glob("data-noleap*.nc")) ...: with xr.open_mfdataset(paths, combine="by_coords") as ds: ...: print(ds.time.encoding) ...: {'zlib': False, 'shuffle': False, 'complevel': 0, 'fletcher32': False, 'contiguous': True, 'chunksizes': None, 'source': '.../data-noleap0.nc', 'original_shape': (7,), 'dtype': dtype('int64'), 'units': 'days since 2000-02-25 00:00:00.000000', 'calendar': 'noleap'}