Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl Monk, Perl Meditation

comment on

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

I beg to differ...

For this substr based implementation it's important to have the temporary array @parts. For the regex it's unimportant! So if we leave the assignment to the array out, the regex is way faster!

Update: Can this be due to the fact that the functions might be called in a scalar context?

use warnings; use strict; use Benchmark qw(cmpthese); my $str = "Just Another Perl Hacker"; print join " ", do_mapstr (), "\n"; print join " ", do_substr (), "\n"; print join " ", do_regex (), "\n"; print "\n"; cmpthese (-1, { mapstr => \&do_mapstr, substr => \&do_substr, regex => \&do_regex, } ); sub do_mapstr { return map substr($str,$_-3,3),(3..length $str); } sub do_substr { my @parts; push @parts, substr $str, $_, 3 for 0 .. length ($str) - 3; return @parts; } sub do_regex { return $str =~ /(?=(...))/g; }


Jus ust st t A An Ano not oth the her er r P Pe Per erl rl l H H +a Hac ack cke ker Jus ust st t A An Ano not oth the her er r P Pe Per erl rl l H H +a Hac ack cke ker Jus ust st t A An Ano not oth the her er r P Pe Per erl rl l H H +a Hac ack cke ker Rate substr mapstr regex substr 25123/s -- -48% -97% mapstr 48651/s 94% -- -95% regex 1003705/s 3895% 1963% --


In reply to Re^3: finding number of contiguous letters by Skeeve
in thread finding number of contiguous letters by Marknel

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 cooling their heels in the Monastery: (9)
    As of 2020-10-27 20:56 GMT
    Find Nodes?
      Voting Booth?
      My favourite web site is:

      Results (258 votes). Check out past polls.