Question

this might be a silly question but I am not getting it. I tried all ways, maybe I am making a silly mistake somewhere. I am still learning parsing. Your help will surely help me to enhance my knowledge. I want to extract forename and lastname of the authors from the authorlist. I have tried to write the code but not sure if I am right.

use LWP::Simple;
use XML::Simple;
use Data::Dumper;

open (FH, ">:utf8","xmlparsed1.txt");

my $db1 = "pubmed";
my $q = 16404398;
my $xml = new XML::Simple;
$urlxml = "http://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=$db1&id=$q&retmode=xml&rettype=abstract";
$dataxml = get($urlxml);
$data = $xml->XMLin("$dataxml", ForceArray => [qw( MeshHeading AuthorList )]);
print FH Dumper($data);
print FH "Authors: ".join '$$', map $_->{LastName},@{$data->{PubmedArticle}->{MedlineCitation}->{Article}->{AuthorList}->[0]->{Author}};

This gives me the lastname but I want forename as well like ‘Atul J Butte’. Also, as this is a generalized code for any such xml file is it correct to mention [0]? What if its at different position in some other xml file? Is there any other way to do this?
Thank you.

Answer 1

You’re forced into using the first array reference for AuthorList because you set ForceArray => ... AuthorList.

Instead try:

$data = $xml->XMLin("$dataxml", ForceArray => [qw( MeshHeading Author )]);
...
my $author_list = $data->{PubmedArticle}{MedlineCitation}{Article}{AuthorList}{Author};
foreach my $author ( @$author_list ) {
    print "Author: $author->{LastName}, $author->{ForeName}\n";
}
# Author: Butte, Atul J
# Author: Kohane, Isaac S

Note that $data->{foo}->{bar} is equivalent to $data->{foo}{bar}