Beefy Boxes and Bandwidth Generously Provided by pair Networks
No such thing as a small change
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??

The Orcish Maneuver is a term coined by Joseph Hall in his book "Effective Perl Programming" (co-authored by merlyn). Here's the essence of it:

my @sorted = sort { ( $times{$a} ||= -M $a ) <=> ( $times{$b} ||= -M $b ) } @old_array;

The "orcish" (a bad attempt at humor: "or cache") maneuver basically caches the results of an expensive lookup using the ||= operator. This operator says, in the above code, that $times{$a} will be evaluated or, if it is false, set it to the value of -M $a. (-M is the file test operator for last modified time). This allows you to cache the results of -M rather than call it every time. This has the same effect as:

for ( @old_array ) { $times{ $_ } = -M $_; } my @sorted = sort { $times{$a} <=> $times{$b} } @old_array;

Cheers,
Ovid

Join the Perlmonks Setiathome Group or just click on the the link and check out our stats.


In reply to (Ovid) Re: Orcish Maneuver by Ovid
in thread Would you use 'goto' here? by Ovid

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!
  • 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, 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, 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.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others drinking their drinks and smoking their pipes about the Monastery: (15)
    As of 2015-07-06 17:05 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (77 votes), past polls