asked on

php usort

I have this xml file from my YouTube account:
<?xml version="1.0"?>
<YouTubeVideos>
      <title>Video Title
            <video img="//i2.ytimg.com/vi/AhXBvK0x9fg/default.jpg" id="AhXBvK0x9fg" part="17"/>
            <video img="//i1.ytimg.com/vi/PzEdUMOBMRg/default.jpg" id="PzEdUMOBMRg" part="16"/>
            <video img="//i2.ytimg.com/vi/Q4-j5zQLr2A/default.jpg" id="Q4-j5zQLr2A" part="15"/>
...
<video img="//i2.ytimg.com/vi/Q4-j5zQLr2A/default.jpg" id="Q4-j5zQLr2A" part="1"/>
</title>
</YouTubeVideos>

Now I want to use usort() function to sort by part:

function sortByPart( $a, $b ){
if ( $a[part] == $b[part] )
return 0;
if ( $a[part] < $b[part] )
return -1;
return 1;
}

$file = '../YouTubeVideos.xml';
$xml = simplexml_load_file($file);
if (!empty($xml->title)) {
echo "<div id=\"div-wrap-around-a\">";
foreach ($xml->title as $title) {
$count = count($title);
usort($title->video, 'sortByPart');
foreach ( $title->video as $video ) {
       echo "<a href='#' id='{$video['id']}' title='$title Ph¿n {$video['part']}'><img src={$video['img']} width=50 align=\"absmiddle\" style=\"padding:5px\" /></a>" . "   " .
                  "<a href='#' id='{$video['id']}' title='$title Ph¿n {$video['part']}'>".trim($title)." Ph¿n {$video['part']}</a> "." <img src=\"{$CCT_site['img_path']}videoicon.gif\" />" . "<br />";
      }
}
echo "</div>";
}

It's still displaying part 17 down to 1.

Thanks in advance

Beverley Portlock

I wrote an EE article on how to do exactly this

https://www.experts-exchange.com/Web_Development/Web_Languages-Standards/PHP/A_3212-Using-PHP-classes-to-group-data-in-memory.html

Have a look and see if it helps.

ASKER CERTIFIED SOLUTION

babuno5

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Ray Paseur

I am having trouble making sense of the XML string. Install this and run it to see why.

<?php // RAY_temp_aline0508.php
error_reporting(E_ALL);
echo "<pre>";


// TEST DATA FROM THE POST AT EE
$xml = <<<XML
<?xml version="1.0"?>
<YouTubeVideos>
      <title>Video Title
            <video img="//i2.ytimg.com/vi/AhXBvK0x9fg/default.jpg" id="AhXBvK0x9fg" part="17"/>
            <video img="//i1.ytimg.com/vi/PzEdUMOBMRg/default.jpg" id="PzEdUMOBMRg" part="16"/>
            <video img="//i2.ytimg.com/vi/Q4-j5zQLr2A/default.jpg" id="Q4-j5zQLr2A" part="15"/>
            <video img="//i2.ytimg.com/vi/Q4-j5zQLr2A/default.jpg" id="Q4-j5zQLr2A" part="1"/>
       </title>
</YouTubeVideos>
XML;


// MAKE AN OBJECT
$obj = SimpleXML_Load_String($xml);

// VISUALIZE THE OBJECT
var_dump($obj);

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aline0508

ASKER

Thanks.

Ray Paseur

If you make a small modification to the XML string, you can use something like this.
http://www.laprbass.com/RAY_temp_aline0508.php
Outputs:
<video img="//i2.ytimg.com/vi/Q4-j5zQLr2A/default.jpg" id="Q4-j5zQLr2A" part="1"/>
<video img="//i2.ytimg.com/vi/Q4-j5zQLr2A/default.jpg" id="Q4-j5zQLr2A" part="15"/>
<video img="//i1.ytimg.com/vi/PzEdUMOBMRg/default.jpg" id="PzEdUMOBMRg" part="16"/>
<video img="//i2.ytimg.com/vi/AhXBvK0x9fg/default.jpg" id="AhXBvK0x9fg" part="17"/>

No usort() complexity anywhere in sight! HTH, ~Ray

<?php // RAY_temp_aline0508.php
error_reporting(E_ALL);
echo "<pre>";


// A DERIVATIVE OF THE TEST DATA FROM THE POST AT EE
$xml = <<<XML
<?xml version="1.0"?>
<YouTubeVideos>
   <YouTubeVideo>
      <title>Video Title</title>
      <video img="//i2.ytimg.com/vi/AhXBvK0x9fg/default.jpg" id="AhXBvK0x9fg" part="17"/>
      <video img="//i1.ytimg.com/vi/PzEdUMOBMRg/default.jpg" id="PzEdUMOBMRg" part="16"/>
      <video img="//i2.ytimg.com/vi/Q4-j5zQLr2A/default.jpg" id="Q4-j5zQLr2A" part="15"/>
      <video img="//i2.ytimg.com/vi/Q4-j5zQLr2A/default.jpg" id="Q4-j5zQLr2A" part="1"/>
   </YouTubeVideo>
</YouTubeVideos>
XML;


// MAKE AN OBJECT
$obj = SimpleXML_Load_String($xml);

// ACTIVATE THIS TO VISUALIZE THE OBJECT
// var_dump($obj);

// COPY THE VIDEO IMG TAGS INTO A KEYED ARRAY
foreach ($obj->YouTubeVideo->video as $v)
{
    // CREATE A TAG AND AN ARRAY INDEX FROM THE OBJECT
    $tag = $v->AsXML();
    $ndx = (string)$v["part"];

    // USE THE PART NUMBER AS THE ARRAY INDEX KEY
    $arr[$ndx] = $tag;
}

// SORT BY THE KEYS
ksort($arr);

// SHOW THE WORK PRODUCT
foreach ($arr as $video_tag)
{
    echo PHP_EOL . htmlentities($video_tag);
}

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