my @simpsons=("homer","bart","marge","maggie","lisa");
my @females=("lisa","marge","maggie","maude");

my %simpsons=map{$_ =>1} @simpsons;
my %females=map{$_=>1} @females;

# the intersection of @females and @simpsons:
my @female_simpsons = grep( $simpsons{$_}, @females );

# proof it works
print "Female Simpson:\t$_\n" foreach (@female_simpsons);

# the difference of @females and @simpsons

my @male_simpsons=grep(!defined $females{$_}, @simpsons);

# proof it works
print "Male Simpson:\t$_\n" foreach (@male_simpsons);
my %union = ();

# the union of @females and @simpsons
foreach(@females,@simpsons){
    $union{$_}=1;
}

my @union2 = keys %union;

# or just do this
# my @union = (@females, @simpsons);
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