$array = array("amit", "hello", "amit", "world", "hello");
print_r(array_count_values($array));

<?
$array = array("amit", "hello", "amit", "world", "hello");
 
/* Sort into an array */
$i=0;
foreach ($array AS $value){
    $result[$value][]=$i;
    $i++;
    }
/* Dump Result */
echo '<xmp>';
print_r($result);
echo '</xmp><hr>';
 
/* Display Results */
foreach ($result AS $name=>$var) {
    echo $name.' ';
    foreach ($var AS $arrayposition) {
        echo $arrayposition.', ';
        }
    echo '<br>';
    }
?>