Mmm. Best thing to do is run through your file once getting all line locations and writing them to a new fixed-length file. Then you can randomize on that file and easily pop your line out of the original file whenever needed. I'm assuming that with millions of lines to randomly pick from, nobody is going to notice that your line pool is only updated every x number of days.

Or you could convert the entire original file to a fixed-length file, but this requires that the lines be more or less the same length, or you're going to end up using huge amounts of disk space.

In reply to Re: Approach to efficiently choose a random line from a large file by TedPride
in thread Approach to efficiently choose a random line from a large file by Your Mother

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.