This Excel LAMBDA function implements the functionality of F#'s List.allPairs function for creating a cross-join between two lists (vectors)

excel-lambda-list.allpairs.txt

LIST.ALLPAIRS = LAMBDA(list1, list2,
    LET(
        list1Col, TOCOL(list1),
        list2Col, TOCOL(list2),
        list1length, ROWS(list1Col),
        list2length, ROWS(list2Col),
        resultRows, SEQUENCE(list1length * list2length, 1),
        rowIndex1, CEILING(resultRows / list2length, 1),
        rowIndex2, MOD(resultRows - 1, list2length) + 1,
        HSTACK(INDEX(list1Col, rowIndex1), INDEX(list2Col, rowIndex2))
    )
);