Forum: Ruby ,elegant

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Leslie V. (Guest)
on 2005-12-13 19:27
(Received via mailing list)
Hiya!

This function adds commas to a string after every three characters
so a number would be easier to read. It's kinda ugly though, and I can't
help thinking there'd be a elegant Why-esque one or two liner to do
this kind of thing - anyone care to improve it?


def add_commas(str)
  return nil if str.class != String

  ret = ""
  len = str.length
  i = len - 1
  while i >= 0
    ret = str[i].chr + ret
    if ((len-i) % 3) == 0
      ret = "," + ret
    end
    i -= 1
  end
  if ret[0].chr == ","
    ret = ret[1..-1]
  end
  ret
end
James G. (Guest)
on 2005-12-13 19:42
(Received via mailing list)
On Dec 13, 2005, at 11:24 AM, Leslie V. wrote:

> Hiya!
>
> This function adds commas to a string after every three characters
> so a number would be easier to read. It's kinda ugly though, and I
> can't
> help thinking there'd be a elegant Why-esque one or two liner to do
> this kind of thing - anyone care to improve it?

Does this help?

http://rubyurl.com/EOi

James Edward G. II
Leslie V. (Guest)
on 2005-12-13 19:48
(Received via mailing list)
James Edward G. II wrote:

>
> Does this help?
>
> http://rubyurl.com/EOi
>
> James Edward G. II
>
I knew it! This kind of thing makes me crazy! I used to think I was a
good programmer!
unknown (Guest)
on 2005-12-13 20:00
(Received via mailing list)
On Wed, 14 Dec 2005, Leslie V. wrote:

>
> if ret[0].chr == ","
>   ret = ret[1..-1]
> end
> ret
> end

   harp:~ > cat a.rb
   def commafy s
     s.to_s.reverse.scan(%r/.{1,3}/).join(',').reverse
   end

   p(commafy(''))
   p(commafy('4'))
   p(commafy('42'))
   p(commafy('422'))
   p(commafy('4242'))
   p(commafy('42424'))
   p(commafy('424242'))
   p(commafy('4242424'))

   harp:~ > ruby a.rb
   ""
   "4"
   "42"
   "422"
   "4,242"
   "42,424"
   "424,242"
   "4,242,424"

if you want you can play with the pattern so the two reverses aren't
needed...
but this is quicker to write ;-)

-a
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