Hi davido, I have to disagree with you on the efficiency here, because I believe a simple sort is faster here. ;-)

I quickly wrote the following example to test the efficiency of the two different sort.

use strict;
use Data::Dumper;
use Benchmark qw/timethese cmpthese/;

my @letters = 'A'..'Z';
my @array;

# generate array of 1000 random length random upper/lower
# case strings to feed into the test subs.
foreach (0..1000) {
    my $c = $letters [rand 26];
    $c = int(rand 2) ? uc $c : lc $c;
    push @array, $c x (1 + rand 10);
}

cmpthese( timethese(1000, {
        'Schwartzian' => '&sort_schwartzian',
        'Simple' => '&sort_simple',
    }) );

sub sort_schwartzian
{
    my @sorted =
        map { $_->[0] }
        sort { $a->[1] cmp $b->[1] }
        map { [ $_, uc $_ ] } @array;
}

sub sort_simple
{
    my @sorted = sort { uc($a) cmp uc($b) } @array;
}

[download]
And the output is -
Benchmark: timing 1000 iterations of Schwartzian, Simple...
Schwartzian: 16 wallclock secs (16.39 CPU) @ 61.01/s (n=1000)
    Simple: 11 wallclock secs (10.95 CPU) @ 91.32/s (n=1000)
              Rate Schwartzian      Simple
Schwartzian 61.0/s          --        -33%
Simple      91.3/s         50%          --

[download]
It shows that the simple sort is much faster than the Schwartzian sort, perhaps because of all the overheads the Schwartzian sort has. And it demonstrates that the perl built-in uc and lc functions are quite efficient. %^p

In reply to Re: Re: noncase-sensitive sorting by Roger
in thread noncase-sensitive sorting by texuser74

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.