in reply to Parsing Yahoo XML Response

As the error message states there is a problem in line 28, but that is one nasty bit of obfusicated code! Lets break it up a little:

my @list;

if (ref $doc->{Result} eq "HASH") {
     @list = $doc->{Result};
} elsif (ref $doc->{Result} eq "ARRAY") {
     @list = @{$doc->{Result}};
} else {
     @list = ();
}

for( @list ){

[download]

Layed out like that it looks like a lot of work! The guts is that it is supposed to generate a list and iterate over it. The complication is that the list may be generated from an array ref or a hash ref. Note though that the sigil used in the first assignment is for a scalar, yet we know there is actually a reference to a hash, and the lhs expects to see a list. Something isn't right! Changing the line to:

     @list = keys %{$doc->{Result}};

[download]

may be what is required. Assuming that fixes the problem, you can re-obfusicate the code by using nested terniary operators, squeezing white space and munging the lot onto one line as a trap for the next maintainer. :)

DWIM is Perl's answer to Gödel

Replies are listed 'Best First'.
Re^2: Parsing Yahoo XML Response
by ecuguru (Monk) on Jan 06, 2007 at 10:07 UTC
    This seems to be working. Does it look better to you?
    Thanks
    
my $yahoo_response = get($req_url);
my $xmlsimple = XML::Simple->new();
my $yahoo_xml = $xmlsimple->XMLin($yahoo_response);

foreach my $result (@{$yahoo_xml->{Result}}) {
    # Make sure result has a thumbnail
    my $title = $result->{Title};
    my $url = $result->{Url};
    my $click_url = $result->{ClickUrl};
#    $click_url =~ s/&/&/g;
    if (ref($result->{Cache}) eq "HASH") {  ##If it has a Cache at all
        my $cacheUrl = $result->{Cache}->{Url};
        my $cacheSize = $result->{Cache}->{Size};
        $out .= "Record: $count<br>\n";
        $out .= "Title: $title<br>\n";
        $out .= "Url: $url<br>\n";
        $out .= "CacheUrl: $cacheUrl<br>\n";
        $out .= "CacheSize: $cacheSize<br>\n";
    }
    print "out\n$out----\n";
    $out = "";
    $count++;
}

    [download]
[reply]
[d/l]
Re^2: Parsing Yahoo XML Response
by ecuguru (Monk) on Jan 06, 2007 at 09:48 UTC
    thank you for the answer, but I wasn't able to understand all of your suggestions, despite what seems like a very well written set of suggestions. Believe me it's my ignorance to this.
    Did you mean that I should change the for loop to: 
    for( ref $doc->{Result} eq "HASH"?keys %{$doc->{Result}}:ref $doc->{Re
+sult}eq "ARRAY"?@{$doc->{Result}}:() ){

    [download]
    ?? If so, I still get the same error. Is there another way to run the loop? Thanks!
[reply]
[d/l]

      In that case I suggest that you try the "expanded" version of the line - that will be much easier to diagnose. If you still have trouble try generating a code sample that demonstrates the problem without requiring the extranious code. Something like this:

      #!/usr/bin/perl -w
use strict;

my $doc = {Result =>
          {first => 1, second => 2}
          #['first', 'second']
          };

my @list;

if (ref $doc->{Result} eq "HASH") {
     @list = keys %{$doc->{Result}};
} elsif (ref $doc->{Result} eq "ARRAY") {
     @list = @{$doc->{Result}};
} else {
     @list = ();
}

for (@list) {
     print "$_\n";
}

      [download]

      which prints the following (without errors or warnings):

      first
second

      [download]

      You might also like to use Data::Dump::Streamer to dump the contents of $doc so that you can see what is causing grief in the data.

      DWIM is Perl's answer to Gödel
[reply]
[d/l]
[select]
        GOT IT!!
        I understand what you were saying now, MANY thanks for that secondary followup post. It really helped me understand what you meant before, and really edificated me.
        thanks again!!!
[reply]

In Section Seekers of Perl Wisdom