#!/Perl/bin/perl

use strict;
use warnings;
use Benchmark qw(:all) ;

my $count = 10000000;

cmpthese($count, {
    'tr' => sub {
        my $var = '5,10';
        $var =~ tr/,/./;
    },
    's' => sub {
        my $var = '5,10';
        $var =~ s/(\d{1,3})(?=(?:\d{3}))/$1\,/g
    },
});