Удаление и замена символов в строке

(remove #\o "Harpo Marx")
; "Harp Marx"
(remove #\a "Harpo Marx")
; "Hrpo Mrx"
(remove #\a "Harpo Marx" :start 2)
; "Harpo Mrx"
(remove-if #'upper-case-p "Harpo Marx")
; "arpo arx"
(substitute #\u #\o "Groucho Marx")
; "Gruuchu Marx"
(substitute-if #\_ #'upper-case-p "Groucho Marx")
; "_roucho _arx"
(defparameter *my-string* (string "Zeppo Marx"))
; *MY-STRING*
(replace *my-string* "Harpo" :end1 5)
; "Harpo Marx"
*my-string*
; "Harpo Marx"