What happened?

I'm not sure if this is a bug or a feature but I was expecting this example to work since the new coord is just a slight rewrite of the original dimension coordinate:

```python import xarray as xr

ds = xr.tutorial.open_dataset("air_temperature")

Change the first time value:

ds["air_new"] = ds.air.copy() air_new_changed = ds.air_new[{"time": 0}] * 3 ds.air_new.loc[air_new_changed.coords] = air_new_changed # Works! :)

Add a another coord along time axis and change

the first time value:

ds["air_new"] = ds.air.copy().assign_coords( {"time_float": ds.time.astype(float)} ) air_new_changed = ds.air_new[{"time": 0}] * 4 ds.air_new.loc[air_new_changed.coords] = air_new_changed # Error! :(

Traceback (most recent call last):

Cell In[25], line 5 ds.air_new.loc[air_new_changed.coords] = air_new_changed

File ~\AppData\Local\mambaforge\envs\jw\lib\site-packages\xarray\core\dataarray.py:222 in setitem dim_indexers = map_index_queries(self.data_array, key).dim_indexers

File ~\AppData\Local\mambaforge\envs\jw\lib\site-packages\xarray\core\indexing.py:182 in map_index_queries grouped_indexers = group_indexers_by_index(obj, indexers, options)

File ~\AppData\Local\mambaforge\envs\jw\lib\site-packages\xarray\core\indexing.py:144 in group_indexers_by_index raise KeyError(f"no index found for coordinate {key!r}")

KeyError: "no index found for coordinate 'time_float'" ```