Sorting list of list of elements of a custom class in R?

Question

I have a custom class object (list of tuples). I have defined <.myclass >.myclass and ==.myclass on it as well.

Now I have a

Answer 1

I wanted to make use of internal and supposedly more efficient sort, but doesn't seem like this sort has facility to take custom comparison operator. So I ended up using implementation of quicksort to sort lists of lists at arbitrary index, assuming comparison exists between the elements at that index.

part_qsort <- function(l, idx, low, high) {
    lst <- l
    pivot <- lst[[high]][[idx]]
    i <- low - 1

    for(j in low:(high-1)) {
        if ((lst[[j]][[idx]] < pivot) || (lst[[j]][[idx]] == pivot)) {
            i <- i + 1
            swap(lst[[i]],lst[[j]])
        }
    }
    swap(lst[[(i+1)]],lst[[high]])
    eval.parent(substitute(l <- lst))
    return(i+1)
}

# recursive calls to quicksort
qsort <- function(l,idx,low,high) {
    if (low < high) {
        lst <- l
        pi <- part_qsort(lst,idx,low,high)
        qsort(lst, idx, low, pi-1)
        qsort(lst, idx, pi+1, high)
        eval.parent(substitute(l <- lst))
    }
}

Another thing to look into can be library("rlist") which seems to have a bunch of functions implemented on lists.