issues: 1863676757

What is your issue?

The Problem When I perform simple operations (e.g., +, -, *, /) on DataArray objects, I expected compatible attributes to be maintained, and incompatible attributes to be removed. Even when playing with the available options for keep_attrs, this behavior does not occur. See also #4763 and #2582.

Here is an example showing what happens in each case:

python da1 = xr.DataArray(1, attrs=dict(unit_system='SI', a=7)) da2 = xr.DataArray(2, attrs=dict(unit_system='SI', a=8)) with xr.set_options(keep_attrs='default'): result = da1 + da2 result.attrs # {} with xr.set_options(keep_attrs=True): result = da1 + da2 result.attrs # {'unit_system': 'SI', 'a': 7}

Desired behavior: python result.attrs # {'unit_system': 'SI'} That is to say, I want attributes with conflicting values to be discarded, and all other attributes to be maintained.

Suggested Fix This is similar to the "drop_conflicts" option for merging attrs, from xarray.merge. I suggest that "drop_conflicts" be added as an option for keep_attrs. For example, I would like to be able to do: python with xr.set_options(keep_attrs="drop_conflicts"): result = da1 + da2 result.attrs # {'unit_system': 'SI'} If anyone else is able to add this option into the code, that would be amazing!

Or, if there is already a way to accomplish this behavior, I would appreciate any advice on how to do it.

Output of xr.show_versions()