Perl SimpleXML: cómo acceder a un valor sin clave

I've got an XML file, When I do a print Dumper on my now $data->{Foo}, Obtengo el siguiente resultado. 

$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.

Gracias,

Dan

preguntado el 03 de mayo de 12 a las 18:05

Also tried a few different variations: $data->{foo}->{bar}[1] $data->{foo}->{1}->{bar} -

{bar} no es lo mismo que {Bar}. Please say what you mean and mean what you say. -

sorry, excuse the case sensitivity mistake. it's corrected now. -

1 Respuestas

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

Si usted dice $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.

Si usted dice $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 para más información.

contestado el 03 de mayo de 12 a las 19:05

Looking at this again, you may be able to leave out all '->'s after the first one, resulting in $data->{Foo}[1]{Bar}; - Sean O'Leary

You can (and I dare say debemos) leave out all -> después del primero. $data->{Foo}[1]{Bar} es lo mismo. - derobert

Yeah, I think should is correct. I've just been using a few other languages lately, and wasn't 100% until I tested it. Post first, answer questions later. :) - Sean O'Leary

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