Perl Sorting Issue

acezone

Hi All,

I am into a situation and loooking for all you feedback on the issue. As I generate a DCR with "DATE" field, it updates XML file based on the logic. If I generate a DCR ("Article0") with date ("03/31/2010"), then this entry will get updated in the XML. Later I generate another DCR ("Article1") with date ("05/31/2010"), then this entry is placed after "Article0" entry. Similarly, I generate another DCR ("Article2") with date ("06/15/2010"), then this entry is placed after "Article1" entry.

Condition is that next time when I regenerate "Article1" DCR, it should now not be after "Article1" entry in XML but should stay as it was there earlier. Also as a thumb rule any entry with recent date should appear as first entry. So summary is entries in XML should go like this:

Article2
Article1
Article0
...
.. so on

Basically idea is to compare the dates and then depending on the logic outcome, entry in the XML should take place. This means that XML should be updated after reading the respective node / element.

I would be highly thankful if you may kindly provide your feedback and pointer in order to resolve the issue.


For reference I am displaying the XML file output:

<NewsArticles>
<Article Date="03/31/2009">Article1</Article>
<Article Date="10/06/2010">Article4</Article>
<Article Date="03/31/2009">Article2</Article>
<Article Date="03/31/2009">Article3</Article>
<Article Date="10/06/2010">Article5</Article>
</NewsArticles>

whereas in the output it should apear as:

<NewsArticles>
<Article Date="10/06/2010">Article5</Article>
<Article Date="10/06/2010">Article4</Article>
<Article Date="03/31/2009">Article3</Article>
<Article Date="03/31/2009">Article2</Article>
<Article Date="03/31/2009">Article1</Article>

</NewsArticles>


Attached are the other are :

ArticleSort.ipl --- > Sorting the Article based on the date
PopulateNews.php ---> For this XML is parsed in order to populate the look and feel of the page.

Regards,
Ace

Adam Stoller

I'd recommend that you build up a hash of array references, where the key is the date in YYYYMMDD format and the value is a reference to an array of the rootnodes of the articles themselves, then you can just use a normal sort of the keys of the array, followed by a sort of the titles (or whatever) within the rootnodes of the array to organize the outputting of your content.

E.g.: something like:

...
my %articles;
foreach my $articleNodeElem (@$articleNodeArr) {
    my $dateVal = fixdate($articleNodeElem->getAttribute('Date'));
    my $articleDCR = ...; # presumably you can get the vpath to the article DCR yourself
    push (@{$article{$dateVal}}, $parser->parsefile($articleDCR));
}

foreach my $date (sort keys %articles) {
    foreach my $art (sort { somefunc } @{$articles{$date}}) {
        # output the relevant information from $art as an XML:OM object
    }
}
...

sub somefuc {
    return $a->getNodeValue(...) cmp $b->getNodeValue(...);
}

sub fixdate {
   my $in = shift;
   if ($in =~ m|^(\d{2})/(\d{2})/(\d{4})|) {
      return "$3$1$2";
   }
   return $in; # unmodified
}