Hello levW,

Although each member of the sample data starts with Patch_, I would still play it safe and allow for the possibility of a different prefix:

use strict;
use warnings;

my @array = qw(Patch_1.0 Patch_2.0 Patch_3.1 Patch_5.0 Patch_4.2 Patch
+_6.0
               Patch_7.0 Patch_8.0 Patch_9.3 Patch_10.2 Apatch_11.0);

@array = sort patch_sort @array;

print "$_\n" for @array;

sub patch_sort
{
    my ($a_name, $a_version) = $a =~ / (\w+) _ ([\d.]+) $ /x
        or die 'Invalid lhs, stopped';

    my ($b_name, $b_version) = $b =~ / (\w+) _ ([\d.]+) $ /x
        or die 'Invalid rhs, stopped';

    return $a_name    cmp $b_name ||
           $a_version <=> $b_version;
}
[download]

Output:

18:22 >perl 1860_SoPW.pl
Apatch_11.0
Patch_1.0
Patch_2.0
Patch_3.1
Patch_4.2
Patch_5.0
Patch_6.0
Patch_7.0
Patch_8.0
Patch_9.3
Patch_10.2

18:22 >
[download]

See sort.

Update 1: Better yet, just use the Sort::Naturally module from CPAN:

use strict;
use warnings;
use Sort::Naturally;

my @array = qw(Patch_1.0 Patch_2.0 Patch_3.1 Patch_5.0 Patch_4.2 Patch
+_6.0
               Patch_7.0 Patch_8.0 Patch_9.3 Patch_10.2 Apatch_11.0);

@array = nsort @array;

print "$_\n" for @array;
[download]

for the same result.

Update 2: I should have read the documentation for Sort::Naturally more carefully: :-(

I define "numeric substring" just as sequences matching m/\d+/ -- scientific notation, commas, decimals, etc., are not seen.

Thanks salva: good catch!

Hope that helps,