It makes sense when your Benchmark tests say it's a problem but not prior. Consider that you're also making a copy of the data which might have it's own implications (unless you get Copy-On-Write (unless that's only a perl6ism)). I'd almost consider this sort of thing right along with the my ($a); vs my $a; optimization. I'd do it for notational convenience but not much else (unless you really do have thousands of entries in your hash and you really, really, really, really care about the pico seconds you're losing ...).

Update: There is a difference between my ($foo) and my $foo - one has to include an extra OPCODE or two to coerce the scalar into list context while the other is already there. I'll leave it to you and B::Terse to figure out which one is "cheaper".

__SIG__
printf "You are here %08x\n", unpack "L!", unpack "P4", pack
  "L!", B::svref_2object(sub{})->OUTSIDE;

[download]

In reply to Re: Should we bother to save hash lookups for performance? by diotalevi
in thread Should we bother to save hash lookups for performance? by dlink

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.