Re: elisp to put commas a number?

[Rupert Swarbrick <rswarbrick@gmail.com>]

[Dammit, hit 'r' rather than 'f' in Gnus. Sorry "The Quiet Center"
that you'll get this twice]

The Quiet Center <thequietcenter@gmail.com> writes:
> Hello, does anyone have any code to put commas in a number?

> ...

> Here is an example of what I want:
>
> (commify (* 130 70491))
> 9,163,830


'Ow about this?

(defun commify (n &optional comma-char)

 (unless comma-char (setq comma-char ","))

 (with-temp-buffer
   (insert (format "%s" n))
   (while (> (- (point)
                (line-beginning-position))
             (if (>= n 0) 3 4))
     (backward-char 3)
     (insert comma-char)
     (backward-char 1))
   (buffer-string)))


Try:

(commify (* 130 70491) ".")
(commify (* -13 70491))


I just wrote it, so fingers crossed it does the right thing! Not sure
whether there's a way to find the locale's choice for comma-char,
though.


Rupert