[RESOLVED] Need help trying to set an array based on if a line exists

Arenlor

Here is the PHP section, it's running through an XML file of my own creation and is outputting it in a way that I like. I'm still working on design right now, but part of what I want to do is create a list of all the names. The problem is that by how the XML document is that I created they won't necessarily have a last name given.
Below is the PHP code for that section.

elseif(ereg('<name>',$line)){
    echo '<h2>';
}
elseif(ereg('<first_name>[A-Za-z ]+</first_name>',$line)){
    list($l,$line) = split('>',$line);
    list($line,$l) = split('<',$line);
    echo $line;
    if($i==''){$i=0;}
    else{$i++;}
    $first[$i]=$line;
}
elseif(ereg('<last_name>[A-Za-z ]+</last_name>',$line)){
    list($l,$line) = split('>',$line);
    list($line,$l) = split('<',$line);
    echo " ".$line;
    $last[$i]=$line;
}
elseif(ereg('</name>',$line)){
    echo "</h2>\n";
}

The code works fine how it is right now, but I've just decided to add the arrays. I don't know enough about arrays to know if this will work how I want it to, so that I can have it do a loop something like this:

for($r=0;$r<=$i;$r++){
    echo '<p><a href="#'.$r.'">'.$first[$r].' '.$last[$r].'</a></p>';
}

If you need any further information let me know, thanks in advance.

Weedpacket

Two incidental points first:

Have you considered using the XML functions to read your XML?
The ereg and split functions are being deprecated in favour of preg_match and preg_split (although in your case the latter would be better replaced by explode).

Back to it:
"Does it work?" can usually be best solved by trying it, but I'm a bit leery. I'd find it much easier to verify correctness if I used a smarter data format. Each <name> you read, obtain $first_name and $last_name (if it exists) and:

$names[] = array('first'=>$first_name, 'last'=>$last_name);

If $last_name doesn't exist then set it to '' instead (instead of leaving it uninitialised, which PHP will whinge about if you try to use it later). This will ensure that the first and last names will remain tied together (if you did something to $last, such as sorting them, will you be able to readjust $first to match?)

Then your loop would be

for($i=0, $count=count($names); $i<$count; $i++)
{
   echo $names['first'][$i].' '.$names['last'][$i]; // Well you get the idea
}

Arenlor

I hadn't thought of initializing it. Now I have it as follows, which should work how I want it to, thanks. I'm doing this just for fun to get use to XML actually, after I get this looking how I want it to I'm going to attempt to use XSL to copy it. So just practice.

elseif(ereg('<first_name>[A-Za-z ]+</first_name>',$line)){
    list($l,$line) = split('>',$line);
    list($line,$l) = split('<',$line);
    echo $line;
    if($i==''){$i=0;}
    else{$i++;}
    $first[$i]=$line;
    $last[$i]='';
}
elseif(ereg('<last_name>[A-Za-z ]+</last_name>',$line)){
    list($l,$line) = split('>',$line);
    list($line,$l) = split('<',$line);
    echo " ".$line;
    $last[$i]=$line;
}