Поиск символа в строке

(find #\t "The Hyperspec contains approximately 110,000 hyperlinks." :test #'equal)
; #\t
(find #\t "The Hyperspec contains approximately 110,000 hyperlinks." :test #'equalp)
; #\T
(find #\z "The Hyperspec contains approximately 110,000 hyperlinks." :test #'equalp)
; NIL
(find-if #'digit-char-p "The Hyperspec contains approximately 110,000 hyperlinks.")
; #\1
(find-if #'digit-char-p "The Hyperspec contains approximately 110,000 hyperlinks." :from-end t)
; #\0
(position #\t "The Hyperspec contains approximately 110,000 hyperlinks." :test #'equal)
; 17
(position #\t "The Hyperspec contains approximately 110,000 hyperlinks." :test #'equalp)
; 0
(position-if #'digit-char-p "The Hyperspec contains approximately 110,000 hyperlinks.")
; 37
(position-if #'digit-char-p "The Hyperspec contains approximately 110,000 hyperlinks." :from-end t)
; 43