alifestd_mark_prev_sibling_id_polars

alifestd_mark_prev_sibling_id_polars(phylogeny_df: DataFrame, *, mark_as: str = 'prev_sibling_id') → DataFrame

Add column prev_sibling_id, the next-lowest id sharing the same parent.

The output column name can be changed via the mark_as parameter.

If no such sibling exists, marks own id.