From: Swami Tota Ram Shankar <tota_ram@india.com>
To: help-gnu-emacs@gnu.org
Subject: Re: string to list or string to array
Date: Sun, 21 Oct 2012 12:03:10 -0700 (PDT) [thread overview]
Message-ID: <4e87f58c-72fc-457b-8596-c792c39472e5@m4g2000yqb.googlegroups.com> (raw)
In-Reply-To: 87pq4c848a.fsf@kuiper.lan.informatimago.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.
next prev parent reply other threads:[~2012-10-21 19:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-21 10:37 string to list or string to array Swami Tota Ram Shankar
2012-10-21 11:16 ` Pascal J. Bourguignon
2012-10-21 19:03 ` Swami Tota Ram Shankar [this message]
2012-10-21 20:22 ` Pascal J. Bourguignon
2012-10-23 1:16 ` Style Issues in Lisp and Scheme programming, setq versus let ... and onion structure with multiple cores or eyes or kernels " Swami Tota Ram Shankar
2012-10-23 2:36 ` PJ Weisberg
[not found] ` <mailman.11503.1350959781.855.help-gnu-emacs@gnu.org>
2012-10-23 3:02 ` Swami Tota Ram Shankar
2012-10-24 15:03 ` Stefan Monnier
2012-10-25 3:20 ` gnuist007
2012-10-25 8:25 ` José A. Romero L.
2012-11-21 21:56 ` Pascal J. Bourguignon
2012-10-23 8:15 ` Pascal J. Bourguignon
2012-10-24 8:05 ` Thien-Thi Nguyen
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