Question

I’ve got an XML file, When I do a print Dumper on my now $data->{Foo}, I get the following output.

$VAR1 = [
          {
            'Bar' => { 
                       ...etc...
                     }
          },
          {
            'Bar' => {
                       ...etc2...
                     }
          }
         ];

How do I print what’s under the second Bar? I tried:

$data->{Foo}{1}->{Bar}

But that’s incorrect syntax.

Thanks,

Dan

Answer 1

You’re going to get in trouble if you leave out the first ‘->’.

If you say $foo->[0] Perl thinks that foo is a scalar that’s a reference to an array, and then returns the first element of that referenced array.

If you say $foo[0] Perl thinks that foo is an array, and returns it’s first element.

You also need to be careful about [] vs. {}. [] are for array lookups, {} are for hash lookups. Perl can convince an array that it’s a hash if it really wants to, with surprising results sometimes.

So, given all that, you need to say something like this:

$data->{Foo}[1]{Bar};

or more pedantically:

$data->{Foo}->[1]->{Bar};

Given the comments below, the first form is preferred for what I think are pretty obvious reasons. See ‘Using References’ in perldoc perlref for more details.