going berserk on the manipulation pipeline

script.pl

@@ -6,11 +6,11 @@ use Data::Dumper;
 use Text::SimpleTable::AutoWidth;
 use WWW::Mechanize ();
 use List::AllUtils qw/ sum pairmap /;
-use List::UtilsBy qw/ nsort_by /;
+use List::UtilsBy  qw/ nsort_by partition_by /;
 
 use experimental qw/ signatures /;
 
-unless(caller) {
+unless (caller) {
     my $ts = get_mersenne_results();
 
     generate_output_table($ts)->draw;
@@ -41,7 +41,7 @@ sub get_mersenne_results() {
     return extract_first_table($html_string);
 }
 
-sub extract_first_table($html) {
+sub extract_first_table ($html) {
     $html =~ s/\n//g;
 
     my $te = HTML::TableExtract->new( depth => 0, count => 2 );
@@ -54,36 +54,29 @@ sub extract_first_table($html) {
 
 sub generate_output_table ($ts) {
 
-# group GHZ Days results by computer, compute GHZ Days per Day (GHZ Days / Days)
-    my $list;
-
-    foreach my $row ( $ts->rows ) {
-        foreach my $cell ($row) {
-            my $machine  = $cell->[0];
-            my $days = $cell->[4] =~ s/\s//gr;
-            my $ghz_days = $cell->[6] =~ s/\s//gr;
-
-            if ( $days > 0 ) {
-                my $perf = $ghz_days / $days;
-                push $list->{$machine}->@*, $perf;
-            }
-        }
-    }
-
-    # create hash with each computer and its average GHz Days per day
-    my %ranks = pairmap {
-        $a => sprintf "%.0f", sum(@$b)/@$b;
-    } %$list;
-
-    # sort hash by the average and print to screen
     my $tbl = Text::SimpleTable::AutoWidth->new(
         captions => [qw/ Computer GHZDaysPerDay /] );
 
-    $tbl->row( @$_ ) for 
+    # group GHZ Days results by computer, compute GHZ Days per Day (GHZ Days / Days)
+    $tbl->row(@$_) for 
         reverse
-        nsort_by { $_->[1] }
-        pairmap { [$a,$b] }
-        %ranks;
+        nsort_by { $_->[1] } 
+        pairmap { [ $a, $b ] } # group for the sorting
+        pairmap { $a => sprintf "%.0f", sum(@$b) / @$b } # take the mean
+        pairmap { 
+            # calculate our stats
+            $a => [ map { $_->{ghz_days} / $_->{days} } @$b ] 
+        } 
+        partition_by { $_->{machine} } # group by machine
+        grep { $_->{days} > 0 } # skip entries with no days
+        map {  # get the info
+            my $machine  = $_->[0];
+            my $days     = $_->[4] =~ s/\s//gr;
+            my $ghz_days = $_->[6] =~ s/\s//gr;
+
+            +{ days => $days, ghz_days => $ghz_days, machine => $machine }
+        } 
+        $ts->rows;
 
     return $tbl;
 }