example.clj

(defn del-sec
  "Delete a line or section from the lst.  Optional second argument
will force single line deletion rather than deleting an entire
section."
  ([lst]
     (let [start (rand-int (.size lst))
           length (rand-int (- (.size lst) start))]
       (concat (take start lst) (drop (+ start length) lst))))
  ([lst single]
     (let [start (rand-int (.size lst))]
       (concat (take start lst) (drop (inc start) lst)))))