Rashmun;
Splitting a string of DNA into triplets... Out of curiosity, do you plan on translating this into protein? If not, ignore me {grin}. If so, have you looked into BioPerl?

use Bio::Seq;

my $seq = Bio::Seq->new(-seq        => 'atccatccctttaat',
                        -display_id => 'Sequence1',
                        -alphabet   => 'dna');
my $prot = $seq->translate;
print 'Translated sequence is: ',$prot->seq,"\n";
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- robsv