1 loop too many in array iteration

[jms53]

Hello Monks,

Having followed your advice, my simple object is now working. However, I don't understand why the code works as it is.

I have an object, with the following structure:

sub new
{
    my ($class, %attr) = @_;
    my $ref = \%attr;
    my @history;
    $ref->{history} = \@history;
}

I then have a method that pushes an array-ref to @{$ref->{history}}:

sub trans
{
  my @done = ["$time[5]-$time[4]-$time[3]", $type, $amount];
  push @{$self->{history}}, \@done;
}

My problem comes to when I want to see the contents of $self->{history}, I have to use 3 loops, when it's only a 2-dimensional array.

sub statement
{
    #iterate through  @{$self->{history}} in 2 dimensions
    my $self = shift;
    
    for my $index ( 0..$#{ $self->{history} } ) 
    {
         for my $j (0..$#{$self->{history}[$index] } )
         
         {
             for (0..$#{$self->{history}[$index][$j] } )
             {
                 print "$self->{history}[$index][$j][$_]\t";
             }
             print "\n";     
         }
    }
}

If anyone could explain to me why the need for 3 loops (or show me where my de-referencing went awfully wrong), it would be greatly appreciated.

[Athanasius]

Square brackets [] return a reference to an array — i.e., a single scalar value. So the line:

my @done = ["$time[5]-$time[4]-$time[3]", $type, $amount];

assigns an array reference to the first element only ($done[0]) of @done. I think you wanted:

my @done = ("$time[5]-$time[4]-$time[3]", $type, $amount);

which populates the array @done with three scalar values.

Hope that helps,

[tmharish]

Your new does not have a bless.

Did you leave that out of the code fragment here?

[vinoth.ree]

Athanasius++

jms53 if the loop goes like this you try to print your data structure using Data::Dumper module, so that you can get understand how the data get saved.

[jms53]

I didn't see the structure any different from what I was expecting in Data::Dumper, although that is likely to be my lack of experience with Data::Dumper.

Athanasius's correction to the sub made everything work as expected.

Thanks for all the help and wisdom!