№4

Заменить подстроку в строке

(defparameter *my-string* (string "Harpo Marx"))
; *MY-STRING*
(subseq *my-string* 0 5)
; "Harpo"
(setf (subseq *my-string* 0 5) "Chico")
; "Chico"
*my-string*
; "Chico Marx"
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