If you wanted to remove any element in A2 from A1, which might appear in any order. I would convert @A2 to a hash and use grep.

#!/usr/bin/perl
use strict;
use warnings;

my @A1= qw/0 1 6 2 3 7 4 5/;
my @A2= qw/6 7/;

my %hash = map {$_ => 1}@A2;
@A1 = grep {!defined $hash{$_}}@A1;

print "@A1\n";  #prints: 0 1 2 3 4 5
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