I've been trying to see if pre-allocating a array would make a script more efficient. So far my timing tests have not been conclusive. Should the following work? 
my $preAllocDummy = 5000;

# Fake call in order to pre-allocate the array.
example();

# Real call.
example();

sub example {
   # Trying a subtle pre-allocation hack.  Supposedly the space
   # allocated for @array will be preserved for later calls.
   my @array;
   if ($preAllocDummy) {
      print "Trying to preallocate to max size $preAllocDummy\n";
      $#array = $preAllocDummy - 1;
      $preAllocDummy = 0;
      return;
   }

   # Push stuff on the array here.
}

[download]

In reply to array pre-allocation trick by Anonymous Monk

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.