<!DOCTYPE html>
<html>
<body>
<?php
$str = 'one,two,three,four';
// zero limit
print_r(explode(',',$str,0));
print "<br>";
// positive limit
print_r(explode(',',$str,2));
print "<br>";
// negative limit
print_r(explode(',',$str,-1));
?>
</body>
</html>