I need to remove all unique entries from a list of lists such that all lists are the same. I have done this but I'm sure there must be a better way?

Data structure for array paring example 
use strict;
use warnings;

use Data::Dumper;

my $temp =
         [
           [
             '/',
             '/index.html',
             '/products/'
           ],
           [
             '/',
             '/index.html',
           ],
           [
             '/',
             '/index.html',
             '/products/'
           ],
           [
             '/',
             '/index.html',
             '/test.html',
           ]
         ];

# Count for the smallest array
my $size = @{$temp->[0]};
my $numterms = @{$temp};

# Build the initial list
my $seen = {};
map{ $seen->{$_}++} @{$temp->[0]};
my $success = 1;

for(my $i = 1; $i < @{$temp}; $i++)
{
    map { $seen->{$_}++ if exists($seen->{$_});}(@{$temp->[$i]});
}

my @results;
while(my ($key,$value) = each(%{$seen}))
{
    if($value == $numterms)
    {
        push @results,$key;
    }
}

print STDERR Data::Dumper->Dump([\@results]);

[download]
Note that the datastructure is typically two to three times the size of the one above. The code prints (when run): 

C:\WINNT\PROFILES\PROCTOS\DESKTOP>perl test.pl
$VAR1 = [
          '/',
          '/index.html'
        ];

C:\WINNT\PROFILES\PROCTOS\DESKTOP>

[download]


I have seen code for returning all unique elements for lists but not to do this.

Thanks
Simon

In reply to Remove unique elements from a list of lists by simon.proctor

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