>>> "UB" == Uwe Brauer <oub@mat.ucm.es> writes:

> Hi

> I need to replace private information in my org files, but only region wide.

> I found 
> https://www.reddit.com/r/emacs/comments/6pc0ts/sanitize_buffer_by_replacing_words_with_random/

> Where two such functions are discussed, one is even for org files,
> however only buffer wide and the code looks rather complicated to me.

No it was actually quite simple:

(defun randomise-region ()
  "Like `ap/replace-words-randomly', but only replace inside region if it is active.
If the region is not active, replace from point to the end of the
buffer.  The region is never considered active outside
`transient-mark-mode'. "
  (interactive)
  (if (or (and (boundp 'zmacs-region-active-p) zmacs-region-active-p)
	  (and (boundp 'transient-mark-mode) transient-mark-mode mark-active))
      (save-restriction
        (save-excursion
          (narrow-to-region (point) (mark))
          (goto-char (point-min))
          (ap/replace-words-randomly)))
    (ap/replace-words-randomly)))