Not a hash reference... why?

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

I'm trying to learn how to use simple::xml. I have file cmdb_cohes.xml

<?xml version="1.0" encoding="utf-8" ?>
<SDForm>
    <Form name="cmdb_cohesion.html" lang="en_US">
        <ResourceString>
            <tag>en</tag>
            <value>en</value>
        </ResourceString>

        <ResourceString>
            <tag>Cohesion</tag>
            <value>Cohesion</value>
        </ResourceString>

    </Form>
</SDForm>
[download]

I wrote file.pl

use XML::Simple;
use strict;
my $xml = new XML::Simple;
my $data = $xml->XMLin('cmdb_coh.xml');
print $data->{Form}->{ResourceString}->{value};
[download]

and as a result of running this script i get such error "Not a HASH reference at: ...file.pl line 14. Please tell me why? What i need to do to fix this. thanks

Comment on Not a hash reference... why? Select or Download Code

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Re: Not a hash reference... why? by Corion (Patriarch) on Apr 26, 2010 at 11:08 UTC
You have two `ResourceString` tags. Which tag do you expect `$data->{Form}->{ResourceString}` to return? When confronted with an unknown data structure, dumping it using Data::Dumper often helps you understand it. Also see `ForceArray` in the XML::Simple documentation.	[reply] [d/l] [select]
Re^2: Not a hash reference... why? by toliyn (Novice) on Apr 26, 2010 at 11:19 UTC
thanks	[reply]
Re: Not a hash reference... why? by derby (Abbot) on Apr 26, 2010 at 11:13 UTC
`use strict; use warnings; use Data::Dumper; use XML::Simple; my $xml = new XML::Simple; my $data = $xml->XMLin('cmdb_coh.xml'); print Dumper( $data );` [download] -derby	[reply] [d/l]
Re: Not a hash reference... why? by toliyn (Novice) on Apr 26, 2010 at 11:13 UTC
I get it. `use XML::Simple; use strict; my $xml = new XML::Simple; my $data = $xml->XMLin('cmdb_coh.xml'); print $data->{Form}->{ResourceString}->[1]->{value};` [download]	[reply] [d/l]
Re: Not a hash reference... why? by BrowserUk (Patriarch) on Apr 26, 2010 at 11:11 UTC
Not a HASH reference at: ...file.pl line 14. Please tell me why? That's kinda hard to do since your posted script only contains 5 lines... I guess we could download your xml, & put it in a file with the right name. Download your script put it in another file. Install XML::Simple; and then run the script to see what error it actually produces and where... Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. RIP an inspiration; A true Folk's Guy	[reply]
Re: Not a hash reference... why? by arc_of_descent (Hermit) on Apr 26, 2010 at 20:39 UTC
I prefer to use the debugger when I need to inspect data structures. The x command is excellent for this. It can inspect arrays, hashes as well as objects. You can then use the p command to print out your references and check whether they are fine. perldebug	[reply]
Re: Not a hash reference... why? by Anonymous Monk on Apr 26, 2010 at 13:22 UTC
Hello! For tracking data structure i recommend you to use Data::Dumper module. Just do something like below: .... use Data::Dumper; use XML::Simple; use strict; my $xml = new XML::Simple; my $data = $xml->XMLin('cmdb_coh.xml'); print Dumper($data),"\n"; And then inspect your data structure	[reply]