fn group_rows_indices(
elt: SEXP,
group: usize,
nrow: usize,
) -> Result<Vec<usize>, DataFrameError>Expand description
Validate and convert one .rows list element — an integer / integerish
vector of 1-based row indices — into a 0-based Vec<usize>. Rejects
non-integer element types and any index outside 1..=nrow.