the best way to go here from a performance perspective?

Best performance means different things to different people. You might want to minimize any, some or all of: inaccuracies, RAM usage, CPU usage, wallclock time, etc.

If we assume wallclock time then the limiting factor is likely to be just reading 30GB of data in the first place. Anything you do with split or substr will probably be dwarfed by that. Start by profiling and see where the bottlenecks lie.

In reply to Re: What is the most efficient way to split a long string (see body for details/constraints)? by hippo
in thread What is the most efficient way to split a long string (see body for details/constraints)? by mikegold10

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