如何从一个Perl数组中添加其他数组中没有的元素?

Given:

考虑到:

my @mylist1;
push(@mylist1,"A");
push(@mylist1,"B");
push(@mylist1,"C");

my @mylist2;
push(@mylist2,"A");
push(@mylist2,"D");
push(@mylist2,"E");
my @mylist1;
push(@mylist1,"A")