Indexing with quantified coordinates

[SGeeversAtVortech]

It seems not possible to index an array with quantified coordinates; see the example below.

import pint
import pint_xarray
import xarray as xr

unit_registry = pint.UnitRegistry(force_ndarray_like=True)
Q_ = unit_registry.Quantity

y = xr.DataArray(name="y", data=[1, 2], coords={"x": [1, 2]})
yq = y.pint.quantify({"y": "km", "x": "s"})
yq.loc[Q_(1, "s")]  # UnitStrippedWarning
yq.loc[Q_(1000, "ms")]  # KeyError

The line yq.loc[Q_(1, "s")] will raise a UnitStrippedWarning and the line yq.loc[Q_(1000, "ms")] will give the same warning and then raise a KeyError.

Should one just avoid using quantified coordinates? Or are there plans to enable indexing with quantities?

[keewis]

you have two choices:

• use pint-xarray's versions of loc / sel: yq.pint.loc[{"x": Q_(1, "s")}] or yq.pint.sel(x=Q_(1, "s"))
• install pint-xarray from main and try out the new PintIndex. This would mean that your code mostly just works (but I've not been able to test this as much as I would have liked, so any feedback would be appreciated)