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Hi,

I am trying to use XML::Simple to parse an xml file. However, the xml file
that I am trying to parse is not in the same format as any of the XML::Simple
examples that I have seen. In all of the examples I have seen, the xml tags
are specific to their contents. In my xml file, the tag names are generic.
Here is a short sample of the xml that I am trying to parse:

<dict>
<key>35</key>
<dict>
<key>Track ID</key><integer>35</integer>
<key>Name</key><string>Earache My Eye (Full Version)</string>
<key>Artist</key><string>Alice Bowie</string>
<key>Genre</key><string>Specialty Rock</string>
<key>Kind</key><string>MPEG audio file</string>
<key>Size</key><integer>6459519</integer>
<key>Total Time</key><integer>322951</integer>
<key>Date Modified</key><date>2005-02-16T12:03:00Z</date>
<key>Date Added</key><date>2005-02-16T11:59:14Z</date>
<key>Bit Rate</key><integer>160</integer>
<key>Sample Rate</key><integer>44100</integer>
<key>Track Type</key><string>File</string>

<key>Location</key><string>file://localhost/M:/1970s/Alice%20Bowie%20-%20Earache%20My%20Eye.mp3/</string>
<key>File Folder Count</key><integer>2</integer>
<key>Library Folder Count</key><integer>1</integer>
</dict>
<key>36</key>
<dict>
<key>Track ID</key><integer>36</integer>
<key>Name</key><string>Earache My Eye</string>
<key>Artist</key><string>Cheech & Chong</string>
<key>Genre</key><string>Specialty Rock</string>
<key>Kind</key><string>MPEG audio file</string>
<key>Size</key><integer>1875968</integer>
<key>Total Time</key><integer>156204</integer>
<key>Date Modified</key><date>2005-02-16T12:03:21Z</date>
<key>Date Added</key><date>2005-02-16T11:59:15Z</date>
<key>Bit Rate</key><integer>96</integer>
<key>Sample Rate</key><integer>32000</integer>
<key>Track Type</key><string>File</string>

<key>Location</key><string>file://localhost/M:/1970s/Cheech%20&%20Chong%20-%20Earache%20My%20Eye.mp3/</string>
<key>File Folder Count</key><integer>2</integer>
<key>Library Folder Count</key><integer>1</integer>
</dict>

I would like to be able to extract things like the "Name", "Artist", and
"Location" but I don't understand how to associate one of the elements of
the key array with one of the elements of the resulting string array.

Jim Gibson wrote:

> In article <th6%d.4321$>, Wes Barris
> <> wrote:

>> <dict>
>> <key>35</key>
>> <dict>
>> <key>Track ID</key><integer>35</integer>
>> <key>Name</key><string>Earache My Eye (Full Version)</string>
>> <key>Artist</key><string>Alice Bowie</string>
>
> [XML lines snipped]
>
> Is that really your XML? You have nested tags with the same name:
> <dict>. You also have <key> tags at different levels. That is going to
> make parsing more difficult.

Nop, for an XML parser that really doesn't matter.

>> </dict>
>> <key>36</key>
>> <dict>
>> <key>Track ID</key><integer>36</integer>
>> <key>Name</key><string>Earache My Eye</string>
>> <key>Artist</key><string>Cheech & Chong</string>
>
> [more lines snipped]
>
>> </dict>
>>
>> I would like to be able to extract things like the "Name", "Artist",
>> and "Location" but I don't understand how to associate one of the
>> elements of the key array with one of the elements of the resulting
>> string array.
>
> You have some very poorly designed XML there. It would be better if it
> were something like
>
> <attribute name="Track ID" value="35"> ...

In some cases that will be considered poor design too. Some people
recommend not to use attributes but elements unless it's meta info on
the element itself.

Better: <track>36</track>
<name>.......</name>
<artist>.....</artist>

> If you cannot change the XML definition, then you are probably better
> off using a SAX parser. XML::SAX:urePerl works, but it is slow. For
> big files, try XML:arser and the expat library. I found it about 75
> times faster in my one use.
>
> In a SAX parser, you define a handler package with callbacks that are
> called for each element in the XML. Then, you will be able to
> associate the <key> value with the subsequent value attribute because
> you will get the callbacks sequentially.

Extremely cumbersome, since, as you already noted the use of elements at
different levels.

I would probably use XML::Twig for this.

--
John Small Perl scripts: http://johnbokma.com/perl/
Perl programmer available: http://castleamber.com/
Happy Customers: http://castleamber.com/testimonials.html

Wes Barris wrote:
> Hi,
>
> I am trying to use XML::Simple to parse an xml file.

XML::LibXML is nice - I use it parse HTML too.

[snip sample data, included below with code]

> I would like to be able to extract things like the "Name", "Artist", and
> "Location" but I don't understand how to associate one of the elements of
> the key array with one of the elements of the resulting string array.

Quick example, using the sample data you posted:

use strict;
use warnings;
use Data:umper;
use XML::LibXML;

my $x = do { local $/; <DATA>; };
my $p = XML::LibXML->new;
my $d = $p->parse_string($x);
my $track = 'Track ID';
my %wanted = map { $_ => 1 } ($track, qw[Name Artist Location] );
my $data;
my $current_track = '';
foreach my $n ( $d->findnodes('//key') ) {
my $t = $n->textContent;
next unless $wanted{$t};
my $v = $n->nextSibling->textContent;
if ($t eq $track) {
$data->{$v} = {};
$current_track = $v;
} else {
$data->{$current_track}{$t} = $v;
}
}

print Dumper($data);

__DATA__
<dict>
<key>35</key>
<dict>
<key>Track ID</key><integer>35</integer>
<key>Name</key><string>Earache My Eye (Full
Version)</string>
<key>Artist</key><string>Alice Bowie</string>
<key>Genre</key><string>Specialty Rock</string>
<key>Kind</key><string>MPEG audio file</string>
<key>Size</key><integer>6459519</integer>
<key>Total Time</key><integer>322951</integer>
<key>Date
Modified</key><date>2005-02-16T12:03:00Z</date>
<key>Date
Added</key><date>2005-02-16T11:59:14Z</date>
<key>Bit Rate</key><integer>160</integer>
<key>Sample Rate</key><integer>44100</integer>
<key>Track Type</key><string>File</string>

<key>Location</key><string>file://localhost/M:/1970s/Alice%20Bowie%20-%20Earache%20My%20Eye.mp3/</string>
<key>File Folder Count</key><integer>2</integer>
<key>Library Folder Count</key><integer>1</integer>
</dict>
<key>36</key>
<dict>
<key>Track ID</key><integer>36</integer>
<key>Name</key><string>Earache My Eye</string>
<key>Artist</key><string>Cheech &
Chong</string>
<key>Genre</key><string>Specialty Rock</string>
<key>Kind</key><string>MPEG audio file</string>
<key>Size</key><integer>1875968</integer>
<key>Total Time</key><integer>156204</integer>
<key>Date
Modified</key><date>2005-02-16T12:03:21Z</date>
<key>Date
Added</key><date>2005-02-16T11:59:15Z</date>
<key>Bit Rate</key><integer>96</integer>
<key>Sample Rate</key><integer>32000</integer>
<key>Track Type</key><string>File</string>

<key>Location</key><string>file://localhost/M:/1970s/Cheech%20&%20Chong%20-%20Earache%20My%20Eye.mp3/</string>
<key>File Folder Count</key><integer>2</integer>
<key>Library Folder Count</key><integer>1</integer>
</dict>
</dict>


HTH - keith