One way to do this is to use another hash.

There are a few notes in the comments.

#!/usr/bin/perl
use strict;
my $datafile = "data.txt";
my @now = localtime(time);

open(FIL,"<$datafile") or die "Can't open data file: $!\n";
my @data = <FIL>;
close(FIL);

my %maxCount;
my %pages;
foreach my $line (@data) {
    # My is a function and will take a list arguement.
    my ($timestamp, $page, $moredata) = split('\|',$line);

    my @hits = localtime($timestamp);
    # Here I create and preset an array with a variable name defined b
+y $page
    ### @$page = (0,0,0,0) if ($$page[3] eq '');

    #Its not quite clear to me when $$page[3] gets set??? Maybe this i
+s something like what you want?
    $pages{$page} = [] unless exists $pages{$page};

    if ($hits[7] == $now[7]) { $pages{$page}[0]++; }
    if ($hits[4] == $now[4]) { $pages{$page}[1]++; }
    if ($hits[5] == $now[5]) { $pages{$page}[2]++; }
    $maxCount{'$page'}++;
}

# Not everyone would endorse this form of list initialisation
my ($dAry, $wAry, $mAry)  = ('','','');

foreach my $page (keys %pages) {
    $dAry .= "$pages{$page}[0],";
    $wAry .= "$pages{$page}[1],";
    $mAry .= "$pages{$page}[2],";
}

#... continued
exit;
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