great regex! me too have forgoten about the look-ahead assertion :( my function that does number beautifying has no less than 8 lines :((
still.. there's a little problem when handling floats: the digits after the dot shouldn't be 'beautified' :(
.. i tried to enhance a little your line but the problem still remains because of the fixed-width look-behind:

$number =~ s/(?<!\.\d)(\d)(?=(\d{3})+(\D|$))/$1,/g;
(this example works for numbers with 5 digits after the dot... variations may me done by modifying the 'quantity' of \d from the look-behind assertion)

couldn't think at anything better now.. maybe you have another bright idea for this too o=)

so, after inserting your wizcraft, my lame tool looks something like this: 

$number =~ s/(\d+)(\.\d+)?/bea_int($1).$2/eg;      
sub bea_int {
   my $kk = $_[0];
   $kk =~ s/(\d)(?=(\d{3})+(\D|$))/$1\,/g;
   return $kk;
}

[download]

--
AltBlue... w8ing 4 a better solution o=Q

In reply to RE: RE: regexp for adding commas to a number by AltBlue
in thread regexp for adding commas to a number by Kozz

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