;;; -*- Emacs-Lisp -*-
;;; stat.el - Small Set of Statistical Functions Written in Emacs-Lisp
;;; (C)2005 by HIROSE, Yuuji [yuuji@gentei.org]
;;; $Id: stat.el,v 1.1 2005/09/20 18:01:24 yuuji Exp $
;;; Last Modified Wed Sep 21 02:51:33 2005 on firestorm
;;; Update Count: 14

;; Usage in ~/.emacs
;; ~~~~~~~~~~~~~~~~~
;; (autoload 'stat "stat" "Statistical Functions" nil)
;; (autoload 'stat-auto-sum "stat" "Add all numbers in preceding lines" t)
;; (global-set-key "\C-c+" 'stat-auto-sum)
;;
;; Usage in *scratch* buffer
;; ~~~~~~~~~~~~~~~~~~~~~~~~~
;; Call 'stat function with arbitrary length numbers and type C-j.
;; Ex.
;; (stat 1 2 3 4 5.9) [C-j]
;;
;; Usage of stat-auto-sum
;; ~~~~~~~~~~~~~~~~~~~~~~
;; The function stat-auto-sum insert a summation of all numbers in the
;; end of preceding lines.  If no numbers found in a contiguous line,
;; calculation is ceased at that line.
;; You can call 'stat-auto-sum repeatedly without erasing old summation
;; because this function removes old summation around the point
;; automatically.
;; 
;; 行末に数値、という連続した行の次の行で 'stat-auto-sum を呼ぶと、ポイ
;; ント位置にそれらの数値の合計が自動挿入される。現在のポイント位置に既
;; に数値がある場合はそれを消してから合計を計算する。

(defun stat1 (p)
  (cond
   ((and (listp p) (atom (car p)))
    (let* ((n (length p))
	   (a (/ (apply '+ p) (float n)))
	   (s2 (apply '+ (mapcar '(lambda (i) (expt (- a i) 2)) p))))
      (list (cons "n" n)
	    (cons "min" (apply 'min p))
	    (cons "max" (apply 'max p))
	    (cons "avg" a)
	    (cons "stdd" (sqrt (/ s2 (1- n)))))))))

(defun stat (&rest p)
  (mapc '(lambda (i)
	   (insert (format "%s\t%s\n" (car i) (prin1-to-string (cdr i)))))
	(stat1 p)))

(defun stat-commaize (n)
  (let ((d (int-to-string (floor n)))
	(s (number-to-string n))
	(r ""))
    (while (string-match "[0-9][0-9][0-9][0-9]$" d)
      (setq r (concat "," (substring d -3) r)
	    d (substring d 0 -3)))
    (concat d r (if (string-match "\\." s) (substring s (match-beginning 0))))))

(defun stat-auto-sum ()
  "Insert the summation of all numbers at the end of preceding lines."
  (interactive)
  (let ((sum 0) lim nstr comma)
    (save-excursion
      (skip-chars-backward "0-9")
      (if (looking-at "[0-9]+")
	  (delete-region (point) (match-end 0)))
      (while (and (not (bobp))
		  (progn
		    (forward-line -1)
		    (setq lim (point))
		    (end-of-line)
		    (re-search-backward "[0-9,.]" lim t)))
	(setq nstr "")
	(while (and (not (bobp)) (looking-at "[0-9.,]"))
	  (let ((c (char-after (point))))
	    (cond
	     ((= c ?,) (setq comma t))
	     (t
	      (setq nstr (concat (char-to-string c) nstr)))))
	  (forward-char -1))
	(setq sum (+ sum (string-to-number nstr)))))
    (insert (if comma (stat-commaize sum) (number-to-string sum)))))


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