Lisp - Splitting Input into Separate Strings

Question

I'm trying to take user input and storing it in a list, only instead of a list consisting of a single string, I want each word scanned in to be its own string. Example:

> (input)
This is my input. Hopefully this works

would return:

("this" "is" "my" "input" "hopefully" "this" "works")

Taking note that I don't want any spaces or punctuation in my final list.

Any input would be greatly appreciated.

Answer 1

split-sequence is the off-the-shelf solution.

you can also roll your own:

(defun my-split (string &key (delimiterp #'delimiterp))
  (loop :for beg = (position-if-not delimiterp string)
    :then (position-if-not delimiterp string :start (1+ end))
    :for end = (and beg (position-if delimiterp string :start beg))
    :when beg :collect (subseq string beg end)
    :while end))

where delimiterp checks whether you want to split on this character, e.g.

(defun delimiterp (c) (or (char= c #\Space) (char= c #\,)))

or

(defun delimiterp (c) (position c " ,.;/"))

PS. looking at your expected return value, you seem to want to call string-downcase before my-split.

PPS. you can easily modify my-split to accept :start, :end, :delimiterp &c.

PPPS. Sorry about bugs in the first two versions of my-split. Please consider that an indicator that one should not roll one's own version of this function, but use the off-the-shelf solution.

Answer 2

There's cl-ppcre:split:

* (split "\\s+" "foo   bar baz
frob")
("foo" "bar" "baz" "frob")

* (split "\\s*" "foo bar   baz")
("f" "o" "o" "b" "a" "r" "b" "a" "z")

* (split "(\\s+)" "foo bar   baz")
("foo" "bar" "baz")

* (split "(\\s+)" "foo bar   baz" :with-registers-p t)
("foo" " " "bar" "   " "baz")

* (split "(\\s)(\\s*)" "foo bar   baz" :with-registers-p t)
("foo" " " "" "bar" " " "  " "baz")

* (split "(,)|(;)" "foo,bar;baz" :with-registers-p t)
("foo" "," NIL "bar" NIL ";" "baz")

* (split "(,)|(;)" "foo,bar;baz" :with-registers-p t :omit-unmatched-p t)
("foo" "," "bar" ";" "baz")

* (split ":" "a:b:c:d:e:f:g::")
("a" "b" "c" "d" "e" "f" "g")

* (split ":" "a:b:c:d:e:f:g::" :limit 1)
("a:b:c:d:e:f:g::")

* (split ":" "a:b:c:d:e:f:g::" :limit 2)
("a" "b:c:d:e:f:g::")

* (split ":" "a:b:c:d:e:f:g::" :limit 3)
("a" "b" "c:d:e:f:g::")

* (split ":" "a:b:c:d:e:f:g::" :limit 1000)
("a" "b" "c" "d" "e" "f" "g" "" "")

http://weitz.de/cl-ppcre/#split

For common cases there is the (new, "modern and consistent") cl-str string manipulation library:

(str:words "a sentence    with   spaces") ; cut with spaces, returns words
(str:replace-all "," "sentence") ; to easily replace characters, and not treat them as regexps (cl-ppcr treats them as regexps)

You have cl-slug to remove non-ascii characters and also punctuation:

 (asciify "Eu André!") ; => "Eu Andre!"

Answer 3

; in AutoLisp usage (splitStr "get off of my cloud" " ") returns (get off of my cloud)

(defun splitStr (src delim / word letter)

  (setq wordlist (list))
  (setq cnt 1)
  (while (<= cnt (strlen src))

    (setq word "")

    (setq letter (substr src cnt 1))
    (while (and (/= letter delim) (<= cnt (strlen src)) ) ; endless loop if hits NUL
      (setq word (strcat word letter))
      (setq cnt (+ cnt 1))      
      (setq letter (substr src cnt 1))
    ) ; while

    (setq cnt (+ cnt 1))
    (setq wordlist (append wordlist (list word)))

  )

  (princ wordlist)

  (princ)

) ;defun

Answer 4

(defun splitStr (src pat /)
    (setq wordlist (list))
    (setq len (strlen pat))
    (setq cnt 0)
    (setq letter cnt)
    (while (setq cnt (vl-string-search pat src letter))
        (setq word (substr src (1+ letter) (- cnt letter)))
        (setq letter (+ cnt len))
        (setq wordlist (append wordlist (list word)))
    )
    (setq wordlist (append wordlist (list (substr src (1+ letter)))))
)

Answer 5

For that task in Common-Lisp I found useful (uiop:split-string str :separator " ") and the package uiop, in general, has a lot of utilities, take a look at the docs https://common-lisp.net/project/asdf/uiop.html#index-split_002dstring.