Beefy Boxes and Bandwidth Generously Provided by pair Networks
The stupid question is the question not asked

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
I found myself also asking this question based on some feedback I received from a recent question I posted - converting hex to char. In this string, unpack and printf were presented as options for converting data. To test the performance for each, I did the following:
#!c:/perl/bin/perl -w use strict; use POSIX qw(strftime); my $x; my $maxint = 200000; my $start = strftime "%H:%M:%S", localtime; for ($x=0; $x <$maxint;$x++) { print unpack "H*", "abc" } my $finish = strftime "%H:%M:%S", localtime; print "$start $finish";
Results: 01:32:57 01:33:48 (51 seconds)
#!c:/perl/bin/perl -w use strict; use POSIX qw(strftime); my $x; my $maxint = 200000; my $start = strftime "%H:%M:%S", localtime; for ($x=0; $x <$maxint;$x++) { printf "%x%x%x",ord('a'),ord('b'),ord('c'); } my $finish = strftime "%H:%M:%S", localtime; print "$start $finish";
Results: 01:31:56 01:32:50 (54 seconds)

In this case, unpack is the clear winner, although the performance difference doesn't become apparent until after 100000 iterations. So, in my opinion, being that TIMTOWTDI, I would look for a performance differential between these methods and opt for the one that requires the least amount of execution time.

The second thing I would check to see if any shelling out can be replaced by an available perl function. I recently wrote a program that required that the date/time stamps in a log file be updated. For this, I made the mistake of relying on shelling out

my $time1 = `date '+%H:%M:%S'`;
when I should have used

my $time1 = strftime "%H:%M:%S", localtime;
Hope this helps.

cheers, -semio

In reply to Re: Optimizing existing Perl code (in practise) by semio
in thread Optimizing existing Perl code (in practise) by JaWi

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, 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?

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

    How do I use this? | Other CB clients
    Other Users?
    Others lurking in the Monastery: (6)
    As of 2019-05-25 08:51 GMT
    Find Nodes?
      Voting Booth?
      Do you enjoy 3D movies?

      Results (152 votes). Check out past polls.

      • (Sep 10, 2018 at 22:53 UTC) Welcome new users!