Re: Keep-only-column

[Marc Tfardy <m-t-o___CUT__IT___@web.de>]

Marc Tfardy schrieb:
> weber wrote:

>  >> Quite frequently I paste stuff which is space-separated.
>  >> I would really like a function that would let me select a region and
>  >> keep only a column, deleting all the rest.
>  >> Anyone knows how I could implement something like this?
>  >> I can do it with regexps, but then I have to come up with a new one
>  >> every time...
>  >> TIA
>  >> HS
>  >
>  > I think the format of "stuff" can't be understood from above :) Here
>  > it is:
>  >
>  > variable BLABLA  =     438438
>  > variable LABLAC  =     312
>  > variable DAUSH  =     43538
>  >
>  > Apply to that region: keep-only-column 2 makes it:
>  > BLABLA
>  > LABLAC
>  > DAUSHD
> 
> 
> 
> Here my draft. Probalby inefficient, but it does the job.
> 
> 
> (defun trim-rectangle (start end)
>   "Trims region to rectangle."
>   (interactive "r")
>   (save-excursion
>     (let ((offset 0)
>           (width 0)
>           (lines (count-lines start end))
>           (i 0))
>       (goto-char start)
>       (beginning-of-line)
>       (setq offset (- start (point)))
>       (goto-char end)
>       (beginning-of-line)
>       (forward-char offset)
>       (setq width (- end (point)))
>       (goto-char start)
>       (while (< i lines)
>         (beginning-of-line)
>         (delete-region (point) (+ (point) offset))
>         (forward-char width)
>         (delete-region (point) (line-end-position))
>         (end-of-line)
>         (forward-char)
>         (setq i (+ i 1))))))
> 

And now slightly tuned version with extra feature - deleting
trailing whitespaces in the region:

(defun trim-rectangle (start end &optional delete-whitespace)
   "Trims region to rectangle. With \\[universal-argument] deletes 
trailing whitespaces."
   (interactive "*r\nP")
   (save-match-data
     (save-excursion
       (let ((offset 0)
             (width 0)
             (lines (count-lines start end))
             (curren-point 0)
             (i 0))
         (goto-char start)
         (setq offset (current-column))
         (goto-char end)
         (setq width (- (current-column) offset))
         (goto-char start)
         (while (< i lines)
           (beginning-of-line)
           (setq current-point (point))
           (delete-region current-point (+ current-point offset))
           (forward-char width)
           (delete-region (point) (line-end-position))
           (if delete-whitespace
               (progn
                 (beginning-of-line)
                 (if (re-search-forward "[ \t]*$" (line-end-position) t)
                     (delete-region(match-beginning 0) (match-end 0)))
                 (end-of-line)))
           (forward-char)
           (setq i (+ i 1)))))))



regards

Marc