How to store and retreive an array of items from within a hashref

spatterson has asked for the wisdom of the Perl Monks concerning the following question:

*update* Thanks ikegami, that sorted it

I have some code with a couple of different classes. One element of object A is an array populated on-the-fly with multiple objects of class B

class A constructor: (roughly)

my $A = {};
bless $A, 'class A';
$A->{arrayholder} = qw//;
return $A
[download]

later on in another method of class A which works, $B1 & $B2 are defined correctly

my $B1 = B->new();
my $B2 = B->new();
my @Bees;
push @Bees, $B1, $B2;
[download]

Then class A calls a method on every class B object it contains

foreach my $B ($A->{arrayholder}) {
    print Dumper $B;
    print $B->Bfoo;
}
[download]

Which fails with 'cannot call method Bfoo without a package or object reference' and the Dumper line prints the count of $B items (scalar $A->{arrayholder})

So how can I pull the B objects out of the array to run a method on each?

just another cpan module author

Comment on How to store and retreive an array of items from within a hashref Select or Download Code

Replies are listed 'Best First'.
Re: How to store and retreive an array of items from within a hashref by ikegami (Patriarch) on Jul 20, 2007 at 13:47 UTC
It's not printing `scalar $A->{arrayholder})`, it's printing the scalar value of whatever was assigned to `$A->{arrayholder}`, since hash elements (incl `$A->{arrayholder}`) are always scalars. If you wish to store a list in a hash element, create an array containing the list and store a reference to that array in the hash element. (References are scalars.) `$A->{arrayholder} = [ ]; @{ $A->{arrayholder} } = ( $B1, $B2 ); # -or- #push @{ $A->{arrayholder} }, $B1, $B2; foreach my $B (@{ $A->{arrayholder} }) { ... }` [download] Update: Rephrased text to be a bit clearer.	[reply] [d/l] [select]
Re: How to store and retreive an array of items from within a hashref by lima1 (Curate) on Jul 20, 2007 at 13:52 UTC
Is $A->{arrayholder} really an arrayref with objects? Can't see it in your code... `$self->{arrayholder} = \@bees` [download] Then you must dereference the arrayref: `foreach my $B (@{ $A->{arrayholder} } ) { .. }` [download]	[reply] [d/l] [select]
Re: How to store and retreive an array of items from within a hashref by FunkyMonk (Bishop) on Jul 20, 2007 at 14:54 UTC
$A->{arrayholder} = qw//; Assigns undef to `$A->{arrayholder}`. You probably want to assign an empty anonymous arrayref: `$A->{arrayholder} = [];` push @Bees, $B1, $B2; This pushes your B's on to the array `@Bees`, but you don't do anything with it! Surely you can get rid of this array and just do: `push @{ $A->{arrayholder} }, $B1, $B2;` [download]	[reply] [d/l] [select]