How to pull data from complex array in php?

Question

I am creating the post in the following form:

while ( $tracks = mysql_fetch_array($trackstring) ){
    $tracks = mysql_fetch_array($trackstring) ){
echo "<li class="tracklist">
<input type="text" name="tracknum-[$tracks['song_id']]" 
value="".$tracks['song_tracknumber']"/> 
<input type="text" name="trackname[$tracks['song_id']]" 
value="".$tracks['song_title'].""/> 
</li>";
    }

it's creating a $_POST array that looks like this:

Array ( [tracknum] => Array ( [13] => 1 [14] => 2 [15] => 3 ) [trackname] => Array ( [13] => One Beat [14] => Faraway [15] => Oh! ) 

essentially I want
1 - One Beat to go into id=13 2 - Faraway to go into id=14

I can see all the data there, but I'm not really sure how to manipulate it... I'm not so hot with arrays. How do I reference these with $_POST['????'] involving the id values

Answer 1

use

$_POST['trackname'][13]

to get "One Beat".

Answer 2

Try to use

print_r($_POST);

That will give you your POST clearly indented, so you can easily navigate through it.

And then, edit your question to sound more clear, if you still need help.

Answer 3

big thanks to cranial-bore at the sitepoint forums :)

$tracknum = $_POST['tracknum'];
$trackname = $_POST['trackname'];
if(count($tracknum) == count($trackname)){ // make sure both the array have same elements
    foreach($tracknum as $songid=>$tracknumber){
        $song_tracknumber = $tracknum[$songid];
        $song_title = $trackname[$songid];
        $sql = "UPDATE songs SET song_tracknumber='$song_tracknumber', song_title='$song_title' WHERE song_id=$songid";
    }
}