unpack is the way to go, but one tip is that unpack 'a3' x $n, $str runs a few percent quicker than unpack '(a3)*', $str if you know in advance how many fields there are.

How can you not know in advance how many fields there are (int(length($seq)/3))?

avoiding the allocation, creation and destruction of 10 million concurrent small arrays -- even if you have ample memory for them -- can save a significant amounts of time

Any implementation in mind? Something like the following? 

while ($seq =~ /(.{3})/sg) {
   # Substring in $1
   ...
}

[download]

In reply to Re^2: Fast Way to Split String in to Chunk of Equal Length by ikegami
in thread Fast Way to Split String in to Chunk of Equal Length by neversaint

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