On Tue, 2003-08-05 at 12:07, Warren Brown wrote:
>   If you want to allow a decimal point:
> 
> irb(main):001:0> puts "-123456789.01".gsub(/(\d)(?=\d{3}+(\.\d*)?$)/, '\1,')
> -123,456,789.01
> 
>     - Warren Brown

Immortalized here:

http://rubyforge.org/snippet/detail.php?type=snippet&id=8

Yours,

tom