John Fisher wrote: > > I am trying to figure out if there is a way to do a sort that > doesn't involve putting an entire file in memory. This kind of > thing is available in apps like syncsort, where you give it > arguments and it uses disk space/virtual memory to do the work.
Do a search for "tape sort" and/or "external sort" and/or "merge sort". Also have a look at Volume 3 of "The Art of Computer Programming" by Donald E. Knuth. > All the examples I am finding are slurping it into an array or > even a hash. I have a 10 field comma delimited csv file that I > need to sort first by one field and run it through one of my > scripts. Then sort it by a different field and run it through > another of my scripts. My thought was to write a script to read > in the csv file and rearrange the fields so that the field to > be sorted is first. Then use a unix sort. Then run another > script to put the order by correctly. > A file mockup: > "field oneA",002,"field threeGG","field fourTT", etc... > "field oneD",004,"field threeAA","field fourZZ",etc.. > Say sort field three first, then sort field four second. It sounds like you need to use a real database and create indexes for the fields in question. John -- use Perl; program fulfillment -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
