if you wish to use a for loop then do:
$test = array('one', 'two', 'three', 'four');
for ($i = 0; $i < count($test); $i++) {echo $test[$i] . '<br>';}
however, unless you are still using PHP3, you should use a foreach loop:
$test = array('one', 'two', 'three', 'four');
foreach ($test as $value) {echo $value . '<br>';}