- explode: documentation ( source)
<?php
$groups = "<p> Item1 </p>
<p> Item 2 </p>
<p> Item 3 </p>
<p> Item 4 </p>
<p> Item 5 </p>
<p> Item 6 </p>
<p> Item 7 </p>";
$groups_arr = explode("\n",$groups);
echo "The last element:".$groups_arr[count($groups_arr)-1];
echo "\n";
echo "The 5th element:".$groups_arr[5-1];