That's a feature of XML::Simple - this difference of behavior between a node which happens once or multiple times. Most of the time, when you expect a node that happen one or more times, you want to tell XML::Simple to always return an array of hashes, so you have a uniform way to deal with the data.

That's what ForceArray attribute for. 

$data = XMLin( $xml, ForceArray => [ qw(Layer) ] )

[download]
will guarantee that every time Layer is seen, it creates an array (ref).

Otherwise you'll always have to code something like that: 

my $layers = $data->{Capabilities}->{Layer};
for my $layer ( ref $layers eq 'ARRAY' ? @$layers : ( $layers ) ) {
    # do something to each Layer
}

[download]

In reply to Re: Checking if a variable is an array by ferreira
in thread Checking if a variable is an array by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.