in reply to perl xml and array issue

Note that with the suggested fix, your code will fail if there's only one product or if a product has only one color. A simple fix is to configure the parser with ForceArray => [qw( product color )].

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Re^2: perl xml and array issue
by dezboi (Initiate) on Nov 18, 2010 at 21:09 UTC
    Okay. So I've done a bit of research with ForceArray, but can't seem to make headway with this. When it comes to an item with a single entry like this: 
        <product>
        <title>widget3</title>
        <cost>0.50</cost>
        <rating>S</rating>
        <color>white</color>
    </product>

    [download]
    it returns empty. I have been poking around with my code, but can't seem to get ForceArray to return single item entries. I'm sooo close, yet sooo far...
[reply]
[d/l]

      I don't understand the question.

      If you use ForceArray => [qw( product color )], 

      foreach $products (@{$file->{product}})    {
    print "Widget: " . $products->{title} ." \n";
    print "Rating: " . $products->{rating} . "\n";
    print "  Cost: " . $products->{cost} . "\n";
    print "Colors: " . join(', ', @{$products->{color}})."\n\n";
}

      [download]

      will work for 

      <shelf>
    <product>
        <title>widget3</title>
        <cost>0.50</cost>
        <rating>S</rating>
        <color>white</color>
    </product>
</shelf>

      [download]

      and 

      <shelf>
    <product>
        <title>widget1</title>
        <cost>0.10</cost>
        <rating>B</rating>
        <color>red</color>
        <color>blue</color>
        <color>green</color>
    </product>

    <product>
        <title>widget2</title>
        <cost>0.25</cost>
        <rating>S</rating>
        <color>pink</color>
        <color>gray</color>
        <color>orange</color>
    </product>
</shelf>

      [download]

      and everything in between. Without ForceArray, you'd need 

      sub list {
   if (defined(ref($_[0])) && ref($_[0]) eq 'ARRAY') {
      return @{ $_[0] };
   } else {
      return $_[0];
   }
}

foreach $products (list($file->{product}))    {
    print "Widget: " . $products->{title} ." \n";
    print "Rating: " . $products->{rating} . "\n";
    print "  Cost: " . $products->{cost} . "\n";
    print "Colors: " . join(', ', list($products->{color}))."\n\n";
}

      [download]

      So what's the problem?

[reply]
[d/l]
[select]
        Okay. I updated the perl script as follows: prod.pl: 
        use XML::Simple;
$xml = new XML::Simple( ForceArray => [qw( product color )]);
$file = $xml -> XMLin('./prod.xml', );

foreach $products (@{$file->{product}})    {
    print "Widget: " . $products->{title} ." \n";
    print "Rating: " . $products->{rating} . "\n";
    print "  Cost: " . $products->{cost} . "\n";
    print "Colors: " . (join ", ", @{$products->{color}})."\n\n";
}

        [download]
        prod.xml 
        <shelf>
    <product>
        <title>widget1</title>
        <cost>0.10</cost>
        <rating>B</rating>
        <color>red</color>
        <color>blue</color>
        <color>green</color>
    </product>

    <product>
        <title>widget2</title>
        <cost>0.25</cost>
        <rating>S</rating>
        <color>pink</color>
        <color>gray</color>
        <color>orange</color>
    </product>

    <product>
        <title>widget3</title>
        <cost>0.50</cost>
        <rating>S</rating>
        <color>white</color>
    </product>
</shelf>

        [download]
        However, output with a single item for "color" remains empty: 
        Widget: widget1
Rating: B
  Cost: 0.10
Colors: red, blue, green

Widget: widget2
Rating: S
  Cost: 0.25
Colors: pink, gray, orange

Widget: widget3
Rating: S
  Cost: 0.50
Colors:

        [download]
        I don't doubt that ForceArrray works, but apparently I just can't figure out the syntax (ie where to plug it in).
[reply]
[d/l]
[select]

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