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Re: Read Some lines in Tera byte file

by BrowserUk (Pope)
on Oct 13, 2010 at 07:12 UTC ( #865029=note: print w/replies, xml ) Need Help??

in reply to Read Some lines in Tera byte file

  • If you need to read line 100 once, read from the beginning.
  • If you know you'll need to read line 100 again, remember where (tell) in the file it was located.

    And while you're at it, you may as well remember where lines 1 through 99 where located also.

  • If you need to read lines at random and often, and quickly: see Re: help reading from large file needed.

    It will take a local file, of ( 8*number-of-lines ) bytes, to hold the index, and roughly the same amount of time as wc -l.

    With a slightly more sophisticated indexer, the size of the index file can be reduced by half.

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