From where "do we know" that the push operation is costly? Compared with what? Because it's a perl build-in it's already highly optimized C code so I don't think that any Perl code can be more efficient.
If you look in perldoc -f push:
[push @ARRAY, LIST] Has the same effect as
   for $value (LIST) {
      $ARRAY[++$#ARRAY] = $value;
   }
but is more efficient.

[download]
IMHO the best way to make your code more efficient, i.e. less-costly, is to recode you script so it's doesn't need a push operation any more.

The most expensive thing with push might be the (re-)allocation of new memory, so if you would initialize the array with the final size at the start, e.g. $#array = 1000;, and use splice instead of push then you might save time. Please post a compare benchmark here if you code that.

In reply to Re: Alternative of Push operation by mscharrer
in thread Alternative of Push operation by mihirjha

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.