I wasn't quite sure if these ABC's can be numbers of if you just have single text letters. If they are single text letters as your test data shows, then I would keep them as strings and use tr to count the number of matches. An eval is needed on tr because the pattern is a run time variable. The below demonstrates this general technique.

There can be all kind of "yeah but's" and "what if's" when intersecting things. I just took the approach of solving the problem with your test data. If the data is actually more complex than shown, then that changes things. 

#!/usr/bin/perl
use warnings;
use Data::Dumper;

my @data=(
"A B C D E F G", "B F G", "D E F",
"A C", "A D E F G", "G",);

my $standard = shift(@data);
print "standard line: 1 => $standard\n";
$standard =~ s/\s+//g;

my %results;
my $original;
my $line_num=2;

foreach  (@data)
{
   $original{$_}=$line_num++;
   $results{$_}= eval "tr/$standard//";
   die @$ if $@;
}

my @sorted_keys = sort {$results{$b} <=> $results{$a} 
                                     or                
                        $original{$a} <=> $original{$b}
                        }keys %results;
foreach (@sorted_keys)
{
   print "line: $original{$_}  => $_  \t: matches $results{$_}\n";
}

__END__
standard line: 1 => A B C D E F G
line: 5  => A D E F G      : matches 5
line: 2  => B F G      : matches 3
line: 3  => D E F      : matches 3
line: 4  => A C      : matches 2
line: 6  => G      : matches 1

[download]

In reply to Re: comparing the elements of an array by Marshall
in thread comparing the elements of an array by young_perl_learner22

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.