I wish to check that the array @regions_A_array does not contain any duplicates and if it does I wish to remove the duplicate.

I personally believe I can't fu**ing believe it: Win, I'm sorry to quote myself, but since you have been extensively harassing the Monastery with remove-duplicates-kinda questions, I'm directing you to one of the answers I gave you back then. I'm astonished and disappointed that you're starting this pantomime over again.

To make this thread minimally interesting (since you can find an actual answer elsewhere) I'll point out that with 5.10 you can easily enough, syntactic-pov-wise, avoid the use of a hash:

#!/usr/bin/perl

use strict;
use warnings;
use List::Util 'shuffle';
use 5.010;

my @new;
$_ ~~ \@new or push @new, $_ for
  shuffle map { ($_) x rand 100 } 'a'..'e';
say "@new";

__END__
[download]

But I wouldn't recommend that!