Welcome to the monastery!

You can simply convert the array into a hash.

#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my @array = qw(dog cat sheep dog dog cat); 

my %hash;

$hash{$_}++ for @array;

# dump the hash to stdout
print Dumper( \%hash ) . "\n";

# print each key-value pairs
for (sort keys %hash) {
  print "$_ -> $hash{$_}\n";
}
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