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/1672#issuecomment-735428830,https://api.github.com/repos/pydata/xarray/issues/1672,735428830,MDEyOklzc3VlQ29tbWVudDczNTQyODgzMA==,90008,2020-11-29T17:34:44Z,2020-11-29T17:35:04Z,CONTRIBUTOR,"It isn't really part of any library. I don't really have plans of making it into a public library. I think the discussion is really around the xarray API, and what functions to implement at first.

Then somebody can take the code and integrate it into the decided upon API.","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,269700511
https://github.com/pydata/xarray/issues/1672#issuecomment-685222909,https://api.github.com/repos/pydata/xarray/issues/1672,685222909,MDEyOklzc3VlQ29tbWVudDY4NTIyMjkwOQ==,90008,2020-09-02T01:17:05Z,2020-09-02T01:17:05Z,CONTRIBUTOR,"Small prototype, but maybe it can help boost the development.

<details>

```python
import netCDF4


def _expand_variable(nc_variable, data, expanding_dim, nc_shape, added_size):
    # For time deltas, we must ensure that we use the same encoding as
    # what was previously stored.
    # We likely need to do this as well for variables that had custom
    # econdings too
    if hasattr(nc_variable, 'calendar'):
        
        data.encoding = {
            'units': nc_variable.units,
            'calendar': nc_variable.calendar,
        }
    data_encoded = xr.conventions.encode_cf_variable(data) # , name=name)
    left_slices = data.dims.index(expanding_dim)
    right_slices = data.ndim - left_slices - 1
    nc_slice   = (slice(None),) * left_slices + (slice(nc_shape, nc_shape + added_size),) + (slice(None),) * (right_slices)
    nc_variable[nc_slice] = data_encoded.data
        
def append_to_netcdf(filename, ds_to_append, unlimited_dims):
    if isinstance(unlimited_dims, str):
        unlimited_dims = [unlimited_dims]
        
    if len(unlimited_dims) != 1:
        # TODO: change this so it can support multiple expanding dims
        raise ValueError(
            ""We only support one unlimited dim for now, ""
            f""got {len(unlimited_dims)}."")

    unlimited_dims = list(set(unlimited_dims))
    expanding_dim = unlimited_dims[0]
    
    with netCDF4.Dataset(filename, mode='a') as nc:
        nc_dims = set(nc.dimensions.keys())

        nc_coord = nc[expanding_dim]
        nc_shape = len(nc_coord)
        
        added_size = len(ds_to_append[expanding_dim])
        variables, attrs = xr.conventions.encode_dataset_coordinates(ds_to_append)

        for name, data in variables.items():
            if expanding_dim not in data.dims:
                # Nothing to do, data assumed to the identical
                continue

            nc_variable = nc[name]
            _expand_variable(nc_variable, data, expanding_dim, nc_shape, added_size)

from xarray.tests.test_dataset import create_append_test_data
from xarray.testing import assert_equal
ds, ds_to_append, ds_with_new_var = create_append_test_data()

filename = 'test_dataset.nc'
ds.to_netcdf(filename, mode='w', unlimited_dims=['time'])
append_to_netcdf('test_dataset.nc', ds_to_append, unlimited_dims='time')

loaded = xr.load_dataset('test_dataset.nc')
assert_equal(xr.concat([ds, ds_to_append], dim=""time""), loaded)
```

</details>","{""total_count"": 2, ""+1"": 2, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,269700511
https://github.com/pydata/xarray/issues/1672#issuecomment-684833575,https://api.github.com/repos/pydata/xarray/issues/1672,684833575,MDEyOklzc3VlQ29tbWVudDY4NDgzMzU3NQ==,90008,2020-09-01T12:58:52Z,2020-09-01T12:58:52Z,CONTRIBUTOR,"I think I got a basic prototype working.

That said, I think a real challenge lies in supporting the numerous backends and lazy arrays.

For example, I was only able to add data in peculiar fashions using the netcdf4 library which may trigger complex computations many times. 

Is this a use case that we must optimize for now?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,269700511