Function rsplit 

pub fn rsplit<D: Dimension>(
    a: &StringArray<D>,
    sep: &str,
    maxsplit: Option<usize>,
) -> FerrayResult<StringArray2>

Right-to-left counterpart of split (#515).

Splits each element on sep starting from the right. With the optional maxsplit cap, only the rightmost maxsplit separators produce splits — leading remainder is kept as one piece. Mirrors numpy.strings.rsplit.

Errors

Returns an error if sep is empty or array construction fails.