Is there a better way to set index as a "permanent" dim rather than a MultiIndex dim?

[ahuang11]

import xarray as xr
import numpy as np
da = xr.tutorial.open_dataset('air_temperature')['air'].isel(time=0)
da[0, 0] = np.nan
da[15, 0] = np.nan

da = da.stack({'index': ('lat', 'lon')}).dropna('index')
da = da.reset_index('index').assign_coords(**{'index': range(len(da['index']))})
da

I want:

To become this:

[keewis]

not sure if there's a better way to do this, but you can combine the expressions and use da.sizes["index"] instead of len(da["index"]):

da = (
    da.stack({"index": ("lat", "lon")})
    .dropna("index")
    .reset_index("index")
    .assign_coords({"index": lambda x: np.arange(x.sizes["index"])})
)

[ahuang11]

Thanks! Didn't know about sizes!