use Data::Dumper;

my @array = ( 'a', 'b', 'c', 'a', 'b' );

#   Iterate through array and increment hash element indexed
#   by the array element - As each hash element must be
#   unique, this allows for a count of each unique array 
#   element to be easily generated.
#
my %hash;
$hash{$_}++ for @array;

print Data::Dumper::Dumper( \%hash );