XML Parsing

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

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Re: XML Parsing by tobias_hofer (Friar) on Jan 31, 2013 at 10:21 UTC
When reading-in xml the XML-Simple provides the xml as a hash-structure. Using Data::Dumper to give a print-out on command line. Thus you can easily see how to access the elements. Some xml-tags which may occur more than once are grouped into an array as far as I remember.. IMHO Data::Dumper is an easy way of exploring structures :-) Hope this helps! Best regards Tobias	[reply]
Re: XML Parsing by tmharish (Friar) on Jan 31, 2013 at 11:21 UTC
You can use XML::Smart to do this like so: `my $xml_obj = new XML::Smart( $xml ) ; my $hash_when_cat_eq_special = ( $xml_obj->{list}{value}( 'category', +'eq', 'special' )->pointer() );` [download] `$hash_when_cat_eq_special will contain: { "/nodes" => { parameter => 1 }, "/order" => ["category", "parameter"], "category" => "special", "parameter" => { "/order" => ["instance", "CONTENT"], "CONTENT" => "\n nameofparameter1\n + ", "instance" => 0, }, }` [download] Of course you can get more specific as follows: `my $xml_obj = new XML::Smart( $xml ) ; my $param_contents = $xml_obj->{list}{value}( 'category', 'eq', 'speci +al' )->{parameter}->content();` [download] `$param_contents will contain: "nameofparameter1"` [download]	[reply] [d/l] [select]
Re^2: XML Parsing by Arunbear (Prior) on Jan 31, 2013 at 12:24 UTC
This way of invoking the constructor can be problematic: `my $xml_obj = new XML::Smart( $xml ) ;` [download] See the section "Indirect Object Syntax" in Invoking Class Methods	[reply] [d/l]
Re^3: XML Parsing by choroba (Cardinal) on Jan 31, 2013 at 12:31 UTC
Do you really use `'XML::Smart'->new` [download] or `XML::Smart::->new` [download] or `new XML::Smart::` [download] ? لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l] [select]
Re^4: XML Parsing by Arunbear (Prior) on Jan 31, 2013 at 13:04 UTC
Re^2: XML Parsing by vmallya (Initiate) on Jan 31, 2013 at 13:16 UTC
First of all thank you Harish. I got the output as suggested. Say for example I had few more child elements under value tag, can I use foreach and extract the elements/sub-elements into a hash/array? Could you give me any sample code to put the contents of $hash_when_cat_eq_special in an hash? Thanks.	[reply]
Re^3: XML Parsing by tmharish (Friar) on Jan 31, 2013 at 14:12 UTC
Quite simply `$hash_when_cat_eq_special` is a pointer to a hash. So you can do your normal hash operations on it. The `->pointer()` function returns this for you. In terms of the foreach: `foreach my $elem ( @{ $xml_obj->{list}{value} } ) { $hash_of_subtree = $elem->pointer() ; }` [download] The advantage here is that `$xml_obj, $xml_obj->{list} ...` are all Objects of type XML::Smart and can always be used as either a hash OR an array. To extract your data you can simply use the 'pointer' function ( `$xml_smart_obj->pointer()` )that will return the hash structure or the 'content' function ( `$xml_smart_obj->content()` ) that will return the contents of a node.	[reply] [d/l] [select]
Re^4: XML Parsing by vmallya (Initiate) on Feb 08, 2013 at 14:14 UTC
Re^5: XML Parsing by tmharish (Friar) on Feb 08, 2013 at 14:25 UTC
Some notes below your chosen depth have not been shown here
Re: XML Parsing by Anonymous Monk on Jan 31, 2013 at 10:21 UTC
XML::Twig can do it all, tutorials and examples at http://xmltwig.org/tutorial/, http://xmltwig.org/article, ?node_id=3989;BIT=use%20XML%3A%3ATwig;BIS=-;a=%5BAnonymous%20Monk%5D;xr=1, ... Re^2: finding XPATH for any node in a XML file, Re: trouble,, need help! (parsing apache jmeter xml, preparing html report), Re: XML::Twig n00b , Re^3: parse xml and store data in array of hashesh	[reply]
Re: XML Parsing by vmallya (Initiate) on Jan 31, 2013 at 13:09 UTC
I used the XML::Smart option. Thanks to TM Harish. I see a warning message. Use of uninitialized value $data in length at /usr/local/lib/perl5/site_perl/5.10.0/XML/Smart/Tree.pm line 159. May be the XML Smart package had some unassigned variable.	[reply]
Re^2: XML Parsing by tmharish (Friar) on Jan 31, 2013 at 13:53 UTC
Yes indeed! Will fix in next update due in a couple of days. Thanks for the report and do report anything else you find either here or on CPAN's RT. Full details whats going on is on this PerlMonks thread.	[reply]