(z) Finding an XML element with XML::Simple

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

Esteemed monks,

I'm trying new grounds, and decided I should really start using XML. Ok, so I read XML::Simple, and it really does seem simple enough. Until I ran into the following problem:

I have the following XML:

<config>
  <gallery>
    <template>admin.tmpl</template>
    <directory>..</directory>
  </gallery>
  <pictures>
    <picture>
      <Mtime>1039101693</Mtime>
      <Size>4096</Size>
      <Type>File</Type>
      <Name>picture.jpg</Name>
    </picture>
    <picture>
      <Mtime>1039036371</Mtime>
      <Size>38633</Size>
      <Type>File</Type>
      <Name>test.jpg</Name>
    </picture>
...
[download]

Now say I want to find the Mtime of 'test.jpg'. In the hashref returned by XML::Simple, it would be here:

  ${$ref->{pictures}->{picture}}[1]->{Mtime}
[download]

(or something similar). But that means that to get the information I have to know it's position in the array. Is there a way to find that position without looping over the whole array? I could defenitly do something like this:

  $xmlref = grep { $_->{Name} eq 'test.jpg' } @{$ref->{pictures}->{pic
+ture}};
[download]

But that seems wasteful. Is there any other way?

Thanks!

-- Dan

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Re: (z) Finding an XML element with XML::Simple by mirod (Canon) on Dec 05, 2002 at 16:41 UTC
You could get to the information more easily if instead of having the name in an element you had it in an attribute. then you could use the `keyattr => Name` option to have XML::Simple use the attribute as a key to a hash instead of using an array. If the attribute was `name` (all lower case) then you would not even have to use the option as it is one of the defaults. As it is I don't think you can avoid the loop.	[reply]
Re: Re: (z) Finding an XML element with XML::Simple by grantm (Parson) on Dec 05, 2002 at 19:49 UTC
Actually, you don't have to put it in an attribute - it works just as well from a child element as long as you haven't used forcearray on that element name. I'd recommend calling XMLin something like this: `my $config = XMLin($filename, keyattr => {picture => 'Name'}, forcearray => ['picture'] );` [download] Then you could access the required value like this: `print $config->{pictures}->{picture}->{'test.jpg'}->{Mtime}, "\n";` [download]	[reply] [d/l] [select]