You double-posted this (Reaped: Array comparison doesn't work). Remember it can take a few minutes for a post to be approved.

As for your problem, arrays flatten when passed as parameters. You should be passing array references instead, to maintain the original containers.

Please see perlsub for details. No point re-stating everything it says unless there's some aspect of that POD that needs clarification. But in brief:

sub flattened {
  my( @a, @b ) = @_;
  return @a;  # Returns everything.
}

sub preserved {
  my( $a_aref, $b_aref ) = @_;
  return @$a_aref;  # Returns only the stuff contained in @$a_aref.
}

my @this = qw( 1 2 3 );
my @that = qw( 4 5 6 );

print "$_\n" for flattened( @this, @that ); # prints 1 2 3 4 5 6.
print "$_\n" for preserved( \@this, \@that ); # prints 1 2 3.
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I am sorry. Didn't realize it double posted but thanks for making this array confusion clear for me!

arrayComp(\@a, \@b);
sub arrayComp {
    my ($aref, $bref) = @_;
    my @a = @$aref;
    my @b = @$bref;
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Moreover, what do you think using (@a, @b) in the parameter list does?

Thanks for your help! I was just passing in array like I was passing in variables. I didn't think there would be much difference but thanks for pointing it out.

That involves using subroutine prototypes and is probably one of the few acceptable uses of prototypes .

It goes as follows:

use Modern::Perl;

sub two_arrays (\@\@) {
    my @first  = @{$_[0]};
    my @second = @{$_[1]};
    say "First array:  @first";
    say "Second array: @second";
}

my @one = qw/een twee drie/;
my @two = qw/nung song saam/;

two_arrays(@one, @two);
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First array:  een twee drie
Second array: nung song saam
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It is not the usual or expected mode of operation of using subroutines and you better document this very clearly or people will get quite confused. But it is there if you want it.

Not much to add, except that it is the same if you want to return two or more arrays from a subroutine: you also need to return references to those arrays, otherwise the arrays get flattened into one single array.