issue_comments: 1263689036

Pandas docs seem stricter than the implementation. From this snippet from pandas source code monotonicity is only required after get_loc fails.

My concern with checking first is that code like below will stop working (if I understand correctly). Is has unique but (alphabetically) unsorted coords (although its order may have meaning for the user). I regularly select a slice by specifying the labels corresponding to the first and last elements I want to extract.

I would suggest in this case to just try while catching any KeyError and raising with a nicer message instead of always checking first.

import xarray as xr da = xr.DataArray([0, 1, 2, 3], coords={'x': ['zero', 'one', 'two', 'three']}) da.sel(x=slice('zero', 'two')) Out[1]: <xarray.DataArray (x: 3)> array([0, 1, 2]) Coordinates: * x (x) <U5 'zero' 'one' 'two'