@codons0 = split /(?:.{3})/, 'atgactaatagcagtgg';  # disable capture with ?:
@codons1 = split /.{3}/,     'atgactaatagcagtgg';  # no parens
{ local $,=':'; print "@codons0\n@codons1\n"; }
__END__
::::::gg
::::::gg