Re: How modify numbers in a region by a multiplier?

[Pascal J. Bourguignon]

Andreas Politz <politza@fh-trier.de> writes:

> Seweryn Kokot <sewkokot@gmail.com> writes:
>
>> Hi,
>>
>> I would like to modify numbers in a region/buffer by a given multiplier.
>>
>> Imagine that I have some numbers
>>
>> 33.444 3333 4433.4443 3344 .34234
>>
>> and I want them multiplied for example by 0.1
>>
>> to receive
>>
>> 3.3444 333.3 443.34443 334.4 .034234
>>
>> I tried with this function I wrote, but it doesn't work properly.
>> Any idea why?
>>
>> (defun my-multiply-numbers-in-region-or-buffer (multiplier)
>>   (interactive "nGive multiplier: ")
>>   (let (beg end object)
>>      (if (use-region-p)
>>         (progn
>>           (setq object "region")
>>           (setq beg (region-beginning))
>>           (setq end (region-end)))
>>       (setq object "buffer")
>>       (setq beg (point-min))
>>       (setq end (point-max)))
>>      (goto-char beg)
>>      (while (re-search-forward "\\([0-9]*\\.?[0-9]*\\)" end t)
>>        (replace-match (format "%.3f" (* (string-to-number (match-string 1)) 
>> multiplier))))
>>      (message "Numbers in %s modified by multiplier %s." object 
>> multiplier)))
>
> The problem is that your regexp matches the empty word.

Or said otherwise:

    Some people, when confronted with a problem, think "I know, I'll
    use regular expressions." Now they have two problems. 

                -- Jamie Zawinski

-- 
__Pascal Bourguignon__                     http://www.informatimago.com/