@saw{ qw( a b c ) } = ( 1, 2, 3 );

##</code><code>##

( $saw{a}, $saw{b}, $saw{c} ) = ( 1, 2, 3 );

##</code><code>##

$saw{a} = 1;
$saw{b} = 2;
$saw{c} = 3;

##</code><code>##

my @arr = (4, 1, 6, 4, 3, 7);
my %saw;
my @new_arr = grep !$saw{$_}++, @arr;
print @new_arr;