Extract the N largest floating point numbers from a large file of floating point numbers

General idea; We use a sorted list to store the N largest numbers and we insert new items as we go. If we need to insert and the list size has reached N, we also delete the lowest value

Lsize=0
while f in stream:
        if L = None
                L = new List
                L.val = f
                L.next = NULL
                Lsize++
        elsif L.val >= f
                continue
        else // L.val < f
                current = L
                while current
                        if current.val > f:
                                next = current.val.next
                                current.next = new List
                                current.next.next = next
                                current.next.val = f
                                if Lsize = N
                                        L = L.next
                        current = current.next