sumup

;; see this gist first http://gist.github.com/285326

(defun sumup()
  "Work out the sum for a cua-mode selected column/rectangle 
and add it to the kill ring, so that it can be pasted in.
Improves on: http://www.emacswiki.org/emacs/AddNumbers as it
works on the more precise, visually appealing & obvious
cua-rectangle selected area, instead of the 'plain' rectangle
select."
  (interactive)
  (save-excursion
    (let ((sum 0)
	  (sumup "*sumup*"))
      (cua-copy-rectangle-as-text)
      (set-buffer (get-buffer-create sumup)) 
      (erase-buffer)
      (yank)
      (goto-char (point-min))
      (while (re-search-forward "[0-9]*\\.?[0-9]+" nil t) 
        (setq sum (+ sum (string-to-number (match-string 0)))))
      (message "Sum: %f" sum)
      (kill-new (number-to-string sum))
      (kill-buffer sumup))))