Perl DSC and or XML::Simple

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

Hey Folks, A quick question if you will... I'm parsing an XML Document into a perl data structure using XML::Simple with the default (Read: No) options. I'm trying to do something with each of the "Map" elements that get parsed out of the XML but i'm not iterating correctly over the structure. Here's my code

my $refdata = XMLin('C:/myxmltest.xml');
print ref($refdata) . "\n";            # Prints out HASH
print ref($refdata->{'Map'}) ."\n";        # Prints out ARRAY
print ref($refdata->{'Map'}[0]) . "\n";        # Prints out HASH

# But when I try ...
foreach my $href ( $refdata->{'Map'} ){
    print $href->{'MapId'} ."\n";
}
[download]

I get a Argument "VC3NEDX$" isn't numeric in hash element at E:\code\xmltest2.pl line 23. Bad index while coercing array into hash at E:\code\xmltest2.pl line 23. Although 'VC3NEDX$' is exactly what i want to print out and is indeed available in $refdata->{'Map'}[0]->{'MapId'} Me thinks i need a little Smack, Up-side the head. Thanks, Dan.

Comment on Perl DSC and or XML::Simple Select or Download Code

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Re: Perl DSC and or XML::Simple by Mr. Muskrat (Canon) on Aug 31, 2002 at 21:03 UTC
I haven't tested this but it should work. `my $refdata = XMLin('C:/myxmltest.xml'); foreach my $href ( @$refdata->{'Map'} ){ print $href->{'MapId'} ."\n"; }` [download] Update: I should explain. You forgot the @. $refdata->{'Map'} is an array reference so you make it @$refdata->{'Map'} and you can act on all of the values that the array reference references. 2nd Update: I forgot the curly braces. Doh!	[reply] [d/l]
Re: Re: Perl DSC and or XML::Simple by Anonymous Monk on Sep 01, 2002 at 11:44 UTC
I Had tried that previously and got a different error, something about "Not an ARRAYin line xxxx" I forgot about using those Dang {} curly braces.. The correct line reads.... `foreach my $href ( @{$refdata->{'Map'} } ) {` Thanks for your help else i probably wouldn't have tried it that way again, Dan.	[reply] [d/l]
Re: Perl DSC and or XML::Simple by grantm (Parson) on Sep 01, 2002 at 23:56 UTC
Try: `foreach my $href ( @{$refdata->{'Map'}} ){ print $href->{'MapId'} ."\n"; }` [download] $refdata->{Map} is an arrayref, to get the array contents you need to stick an '@' on the front and add braces to specify what the '@' applies to. Without the braces it would try to treat $refdata as an arrayref - which it is not. I'm parsing an XML Document into a perl data structure using XML::Simple with the default (Read: No) options I can't recommend that :-) You should at least use: `my $refdata = XMLin('C:/myxmltest.xml', forcearray => [ 'Map' ]);` [download] That way your code won't break if there's only one 'Map' element.	[reply] [d/l] [select]
Re: Re: Perl DSC and or XML::Simple by dataDrone (Acolyte) on Sep 05, 2002 at 00:06 UTC
Thanks for the 'heads up' Grant, I wouldn't have noticed for at least a few days. Always nice to get help from the module's Author, that's what i like about the Perl community.	[reply]