Perl subroutine array and scalar variable parameters

Question

How exactly can I pass both scalar variables and array variables to a subroutine in Perl?

 my $currVal = 1;
 my $currValTwo = 1;
 my @currArray = ('one','two','three');
 my @currArrayTwo =('one','two','three');

 &mysub($currVal, $currValTwo,\@currArray, \@currArrayTwo);

 sub mysub() {

     # That doesn't work for the array as I only get the first element of the array
     my($inVal, $inValTwo, @inArray, @inArrayTwo) = @_;
 }

Answer 1

You need to fetch them as references because you've already passed them as references (by using the \ operator):

my($inVal, $inValTwo, $inArray, $inArrayTwo) = @_;

and then use the references as arrays:

@{$inArray}

Answer 2

You pass the arguments as references, so you need to dereference them to use the values. Be careful about whether you want to change the original array or not.

sub mysub {
    my($inVal, $inValTwo, $inArray, $inArrayTwo) = @_;
    @{$inArrayTwo} = ('five','six','seven');
}

This will change the original @currArrayTwo, which might not be what you want.

sub mysub {
    my($inVal, $inValTwo, $inArray, $inArrayTwo) = @_;
    my @ATwo = @{$inArrayTwo};
    @ATwo = ('five','six','seven');
}

This will only copy the values and leave the original array intact.

Also, you do not need the ampersand in front of the sub name, from perldoc perlsub:

If a subroutine is called using the & form, the argument list is optional, and if omitted, no @_ array is set up for the subroutine: the @_ array at the time of the call is visible to subroutine instead. This is an efficiency mechanism that new users may wish to avoid.

You do not need empty parens after your sub declaration. Those are used to set up prototypes, which is something you do not need to do, unless you really want to.