Re: string to list or string to array

[Swami Tota Ram Shankar <tota_ram@india.com>]

On Oct 21, 4:16 am, "Pascal J. Bourguignon" <p...@informatimago.com>
wrote:
> Swami Tota Ram Shankar <tota_...@india.com> writes:
>
> > Friends, I am trying to read text from a file opened in emacs and
> > recognize it as array or list so that I can do some vector additions
> > using mapcar.
>
> > I am mainly stuck at the stage of converting the string text to array
> > or list.
>
> > The method which I use to locate the text is "looking-at" function and
> > the regexp works.
>
> > (when (looking-at "[[0-9.+-\\ ]+]")
>
>                      ^^
>                      12
>
> The character 1 has the meaning you'd want the character 2 to have.
>
> Your regexp parses as:
>
>      one or more of any character in "[0123456789.+- "
>      followed by "]".
>
> You want:
>
>       (looking-at "\\[[0-9.+-\\ ]+\\]")
>
> The third backslash is optional, but I add it for clarity.
>
>
>
>
>
>
>
>
>
> > some code that is to play around for debugging and messaging and
> > checking the match
> > (forward-char (+ (string-width (match-string 0)) 1))
> > (setq V (match-string 0))
> > (setq V (intern (match-string 0)))
>
> > The cursor is placed on the start bracket, ie "["
>
> > and text looks like for example array of indefinite length
>
> > [17.16 -17.16 17.16 17.16 17.16 17.16 17.16 17.16]
>
> > Please suggest some different solutions that can take the string
> > matched, match-string for example and convert to a list or an array on
> > which I can do mapcars or lambdas.
>
> Since the syntax of this text is exactly the printed representation of
> an emacs lisp vector, you can read it directly with read.
>
> (defun get-vectors-from-buffer ()
>    (let ((vectors '()))
>      (goto-char (point-min))
>      (while (re-search-forward "\\[[0-9.+-\\ ]+\\]" nil t)
>         (goto-char (match-beginning 0))
>         (push (read (current-buffer)) vectors))
>      (nreverse vectors)))
>
> ;; [1 2 3.0] [4 5 6]
> ;; [7 +8 -9]
>
> (get-vectors-from-buffer)
> --> ([[0-9\.+-\\] +]
>      [[0-9\.+-\\] +\\]
>      [17.16 -17.16 17.16 17.16 17.16 17.16 17.16 17.16]
>      [[0-9\.+-\\] +\\]
>      [1 2 3.0]
>      [4 5 6]
>      [7 8 -9])
>

Hi Pascal, Thanks for the reply but there are some problems. I
understood your change to regexp.

However, you are doing too much in your and I need only read one
string at a specific location at a time, not the whole buffer.

Thus, I am having difficulty and need help. Let me write the modified
story again.

(when (looking-at "\\[[0-9.+-\\ ]+\\]")
(forward-char (+ (string-width (match-string 0)) 1))
(setq V (match-string 0))
(setq V (read-from-string (intern (match-string 0))))
;(setq V (read-from-string "[17.16 -17.16 17.16 17.16 17.16 17.16
17.16 17.16]" ))


;      (insert (match-string 0))         ;  print the entire matched
string
;(insert (format "%s" V))
(insert (format "%s" (car (split-string (format "%s" V) " "))))
;; (setq X (make-vector
;;  (/ (length V ) 2)
;;  3 )


)
[17.16 -17.16 17.16 17.16 17.16 17.16 17.16 17.16]


I am using

read-from-string

and I need to get it to work.

but it gives error

Debugger entered--Lisp error: (wrong-type-argument stringp \[17\.16\
-17\.16\ 17\.16\ 17\.16\ 17\.16\ 17\.16\ 17\.16\ 17\.16\])
  read-from-string(\[17\.16\ -17\.16\ 17\.16\ 17\.16\ 17\.16\ 17\.16\
17\.16\ 17\.16\])
  eval((read-from-string (intern (match-string 0))))
  eval-last-sexp-1(nil)
  eval-last-sexp(nil)
* call-interactively(eval-last-sexp)


If I dont use intern, I get some small little thing.

(read-from-string "[17.16 -17.16 17.16 17.16 17.16 17.16 17.16
-17.16]" ))

([17.16 -17.16 17.16 17.16 17.16 17.16 17.16 17.16] . 51)

so I can car it.

should I be using match-string or  data-match or match-data to most
simply get it working  while using "looking-at" ?

so the parsing works which a hard wired string as in the sequential
execution below, but the problem is that its not working with match-
string.

(setq V (car (read-from-string "[17.16 -17.16 17.16 17.16 17.16 17.16
17.16 -17.16]" )))
(mapcar* (lambda(x y)(+ x y)) V V)


Thanks.