(require '[clojure.string :as str])

(def data-string "Substring removing")

;; Cutting by index
(def head (subs data-string 0 9))
;; head is "Substring"

(def tail (subs head 3))
;; tail is "string"

;; Dropping a known piece by its text
(def no-suffix (str/replace data-string " removing" ""))
;; no-suffix is "Substring"

(def no-prefix (str/replace no-suffix #"^Sub" ""))
;; no-prefix is "string"

(println head)
(println tail)
(println no-suffix)
(println no-prefix)