A Schwartzian Transform when all you have to do is parse dates? That will make things *slower*. Creating all those arrays and references adds up.

This could speed up the sorting (because it creates few extra variables and it uses the specially optimised $a cmp $b callback): 

my @sorted =
   map substr($_, 8),
   sort
   map join('', (/(..)-(..)-(....)/)[2,1,0], $_),
   @dates;  # DD-MM-YYYY

[download]

Naïve: 

my @sorted =
   sort {
      join('', ($a =~ /(..)-(..)-(....)/)[2,1,0])
         cmp
      join('', ($b =~ /(..)-(..)-(....)/)[2,1,0])
   }
   @dates;  # DD-MM-YYYY

[download]

Schwartzian Transform: 

my @sorted =
   map $_->[0],
   sort { $a->[1] cmp $b->[1] }
   map [ $_, join('', (/(..)-(..)-(....)/)[2,1,0]) ],
   @dates;  # DD-MM-YYYY

[download]

In reply to Re: Sorting dates with the Schwartzian Transform by ikegami
in thread Sorting dates with the Schwartzian Transform by Wobbel

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.