As presented there is the small cost of calling the sub which is avoided in the second case. However if the test is non-trivial it may be better to localise that in the sub to improve maintainability and clarity of the code and wear the small runtime cost of calling the sub. Almost always you will waste far more time worrying about a few microseconds of overhead than will ever be a problem or repay the worry time.

You may find the replies to Calling a subroutine - which is most efficient? helpful. Bottom line: there's almost no difference so do whatever is easiest to understand and maintain.

Perl reduces RSI - it saves typing

In reply to Re: How to select the code on basis of memory usage and execution time. by GrandFather
in thread How to select the code on basis of memory usage and execution time. by Rapunzel

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.