from typing import List


def parse_combined_columns(eval_data: List[List[str]], index_a: int, index_b: int, delimiter: str = ' - ') -> str:
    """
    Combines two columns worth of data into a single list of comments, separated by a delimiter
    """
    if len(eval_data) <= 1:
        return ''
    return_val = "\\begin{itemize}\n"
    for i in range(1, len(eval_data)):
        item_a = eval_data[i][index_a].strip()
        item_b = eval_data[i][index_b].strip()
        if len(item_a) > 0 and len(item_b) > 0:
            return_val += "\\item %s%s%s\n" % (item_a, delimiter, item_b)
        elif len(item_a) > 0:
            return_val += "\\item %s\n" % item_a
        elif len(item_b) > 0:
            return_val += "\\item %s\n" % item_b
    return return_val + "\\end{itemize}\n"