From: Jim Van Fleet <jim@...>
Date: 2005-02-12T03:04:35+09:00
Subject: Currency formatting with regexp

Hi, all, this is my first post to Ruby-talk, so please be kind-- if 
that's not your natural disposition.

I'm looking to work up some code that turns floats into string-based 
currency values.

I've got an implementation working that's pretty ungodly.  It looks a 
lot like I would program it in Java.  Naturally, once I finished, I 
found some Perl suggestion that looks like this:

sub commify {
     my $text = reverse $_[0];
     $text =~ s/(\d\d\d)(?=\d)(?!\d*\.)/$1,/g;
     return scalar reverse $text;
}

I am a regexp noob.  I experimented with using gsub and this regular 
expression, but I can't seem to get anywhere.  The closest I've come 
replaces the first comma but then eliminates the rest of the number.

Can someone help me figure out what's going on-- or point me to where 
this is already available in Ruby?  (Pickaxe II references neither money 
nor currency, and I don't really want to install extensions just for 
this functionality.)

Thanks so much,

Jim