my %score = ( WPA   => 1,
              WPA2  => 2,
              WEP64 => 3,
              # ...
             );
[download]

Than, just search for the maximum. You might need a reversed hash to retrieve the type back from the maximum.

I'd use a hash for this rather than an array, something along these lines:

%supported_security = (
    "WPA"    => "WPA",
    "WPA2"   => "WPA2",
    "WEP 64" => "WEP 64",
    ...
);
[download]

And then just probe that hash in order of preference of security type:

$best_type = $supported_security{"WPA2"}
    // $supported_security{"WPA"}
    // $supported_security{"WEP 128"}
    // ...
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with // being the logical defined-or operator (see Logical Defined Or); if that's not available on the version of Perl you're using, use || instead.

Another variation on the "quality scoring" hash:

c:\@Work\Perl\monks>perl -wMstrict -le
"use List::Util qw(reduce);
 ;;
 my %quality = qw(WPA2 4  WPA 3  WEP128 2  WEP64 1);
 ;;
 my @available = qw(WPA WPA2 WEP128);
 my $best_available = reduce { $quality{$a} > $quality{$b} ? $a : $b }
+ @available;
 print qq{'$best_available' is best available};
"
'WPA2' is best available
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#!perl
use strict;
use warnings;

my @preferred = qw(best good normal bad worst);
my @routers = qw (asda adsas asdasds);

foreach my $router(@routers){
        my $best_of = best_of($router);
}


sub best_of {
    my $router = shift;
    my %available;
    @available{get_available($router)};# get_available return a list
                                       # used as keys of %available ha
+sh
                                       # for our comfort
    map { return $_ if exists %avalable{$_} } @preferred;

}
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my %available;
@available{get_available($router)};# get_available return a list


c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my %h;
 @h{ qw(a b c) };
 dd \%h;
"
Useless use of hash slice in void context at -e line 1.
{}

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my %h;
 @h{ qw(a b c) } = undef;
 dd \%h;
"
{ a => undef, b => undef, c => undef }
[download]

why set up a hash of type => priorities and search your array for the element with the highest priority?

Thank you all for the quick responses. There are some good methods here which I completely overlooked i.e. using the hash. This looks to be the best solution for what I need but I will have a play and see what works out the best.