Working with Strings in Lisp

(setq s "This is a real live string.")

(elt s 8) ; => #\a

; note that the first position is 0.

; Testing character objects:

(alphanumericp (elt s 7)) ; => NIL

; MUST BE EITHER ALPHA-CHAR-P or

; DIGIT-CHAR-P.

(digit-char-p #\9) ; => 9, i.e., True.

(string-upcase s) ; =>

”THIS IS A REAL LIVE STRING.”