LISP - Modify String

Question

I have to write a program that changes a string's vowels, consonants and other symbols into C, V respectively 0. I've done this but I wonder if there is a more efficient and elegant way to do it. Would appreciate input.

(defun string-to-list (string)
(loop for char across string collect char))

(defun is-vowel (char) (find char "aeiou" :test #'char-equal))

(defun is-consonant (char) (find char "bcdfghjklmnpqrstvwxyz" :test #'char-equal))

(defun letter-type (char)
(if (is-vowel char) "V"
(if (is-consonant char) "C"
"0")))

(defun analyze-word (word-string)
(loop for char across word-string collect (letter-type char)))

Moreover, I would like to make it a string, how could I do that? Should I define a function that would iterate through the list and make it a string or is it an easier way to do it?

This question should be better asked at codereview.stackexchange.com — akluth
– akluth, Commented Apr 2, 2013 at 13:18
Use 'MAP' instead. It would help if your format and indent your code according to typical conventions. — Rainer Joswig
– Rainer Joswig, Commented Apr 2, 2013 at 13:30
Please invest a few minutes to learn how to format Lisp code. — danlei
– danlei, Commented Apr 2, 2013 at 15:55

huaiyuan · Accepted Answer · 2013-04-02 14:15:19Z

2

(defun letter-type (char)
  (cond ((find char "aeiou" :test #'char-equal) #\V)
        ((alpha-char-p char) #\C)
        (t #\0)))

CL-USER> (map 'string #'letter-type "analyze-word")
"VCVCCCV0CVCC"

answered Apr 2, 2013 at 14:15

huaiyuan

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2 Comments

Max Bummer Over a year ago

Though when I type in "spectacuular22ace" it gives me "VCVCCCV0CVCC" and spectacular starts with a v which is a consonant not a vowel and more than that, it only prints one 0 and not two 0.

huaiyuan Over a year ago

You have to replace the "analyze-word" in the above example with your input.

user797257 · Accepted Answer · 2013-04-02 20:56:25Z

0

Just for the sake of the idea:

(defun multi-replace-if (sequence function &rest more-functions)
  (map (type-of sequence)
       (lambda (x)
         (loop for f in (cons function more-functions)
            for result = (funcall f x)
            while (eql x result)
            finally (return result)))
       sequence))

(multi-replace-if "bcdfghjklmnpqrstvwxyz"
                  (lambda (x) (if (find x "aeiouy") #\v x))
                  (lambda (y) (declare (ignore y)) #\c))
"cccccccccccccccccccvc"

answered Apr 2, 2013 at 20:56

user797257

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